diff --git a/example/package-lock.json b/example/package-lock.json
index 3d2a172..3d3e8c1 100644
--- a/example/package-lock.json
+++ b/example/package-lock.json
@@ -2741,7 +2741,8 @@
             },
             "ansi-regex": {
               "version": "2.1.1",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "aproba": {
               "version": "1.2.0",
@@ -2759,11 +2760,13 @@
             },
             "balanced-match": {
               "version": "1.0.0",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "brace-expansion": {
               "version": "1.1.11",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "balanced-match": "^1.0.0",
                 "concat-map": "0.0.1"
@@ -2776,15 +2779,18 @@
             },
             "code-point-at": {
               "version": "1.1.0",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "concat-map": {
               "version": "0.0.1",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "console-control-strings": {
               "version": "1.1.0",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "core-util-is": {
               "version": "1.0.2",
@@ -2887,7 +2893,8 @@
             },
             "inherits": {
               "version": "2.0.3",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "ini": {
               "version": "1.3.5",
@@ -2897,6 +2904,7 @@
             "is-fullwidth-code-point": {
               "version": "1.0.0",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "number-is-nan": "^1.0.0"
               }
@@ -2909,17 +2917,20 @@
             "minimatch": {
               "version": "3.0.4",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "brace-expansion": "^1.1.7"
               }
             },
             "minimist": {
               "version": "0.0.8",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "minipass": {
               "version": "2.3.5",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "safe-buffer": "^5.1.2",
                 "yallist": "^3.0.0"
@@ -2936,6 +2947,7 @@
             "mkdirp": {
               "version": "0.5.1",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "minimist": "0.0.8"
               }
@@ -3008,7 +3020,8 @@
             },
             "number-is-nan": {
               "version": "1.0.1",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "object-assign": {
               "version": "4.1.1",
@@ -3018,6 +3031,7 @@
             "once": {
               "version": "1.4.0",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "wrappy": "1"
               }
@@ -3093,7 +3107,8 @@
             },
             "safe-buffer": {
               "version": "5.1.2",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "safer-buffer": {
               "version": "2.1.2",
@@ -3123,6 +3138,7 @@
             "string-width": {
               "version": "1.0.2",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "code-point-at": "^1.0.0",
                 "is-fullwidth-code-point": "^1.0.0",
@@ -3140,6 +3156,7 @@
             "strip-ansi": {
               "version": "3.0.1",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "ansi-regex": "^2.0.0"
               }
@@ -3178,11 +3195,13 @@
             },
             "wrappy": {
               "version": "1.0.2",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "yallist": {
               "version": "3.0.3",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             }
           }
         },
@@ -4789,11 +4808,6 @@
       "resolved": "https://registry.npmjs.org/etag/-/etag-1.8.1.tgz",
       "integrity": "sha1-Qa4u62XvpiJorr/qg6x9eSmbCIc="
     },
-    "eventemitter3": {
-      "version": "3.1.2",
-      "resolved": "https://registry.npmjs.org/eventemitter3/-/eventemitter3-3.1.2.tgz",
-      "integrity": "sha512-tvtQIeLVHjDkJYnzf2dgVMxfuSGJeM/7UCG17TT4EumTfNtF+0nebF/4zWOIkCreAbtNqhGEboB6BWrwqNaw4Q=="
-    },
     "events": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/events/-/events-3.0.0.tgz",
@@ -5820,13 +5834,20 @@
       "integrity": "sha512-cZdEF7r4gfRIq7ezX9J0T+kQmJNOub71dWbgAXVHDct80TKP4MCETtZQ31xyv38UwgzkWPYF/Xc0ge55dW9Z9w=="
     },
     "http-proxy": {
-      "version": "1.17.0",
-      "resolved": "https://registry.npmjs.org/http-proxy/-/http-proxy-1.17.0.tgz",
-      "integrity": "sha512-Taqn+3nNvYRfJ3bGvKfBSRwy1v6eePlm3oc/aWVxZp57DQr5Eq3xhKJi7Z4hZpS8PC3H4qI+Yly5EmFacGuA/g==",
+      "version": "1.18.1",
+      "resolved": "https://registry.npmjs.org/http-proxy/-/http-proxy-1.18.1.tgz",
+      "integrity": "sha512-7mz/721AbnJwIVbnaSv1Cz3Am0ZLT/UBwkC92VlxhXv/k/BBQfM2fXElQNC27BVGr0uwUpplYPQM9LnaBMR5NQ==",
       "requires": {
-        "eventemitter3": "^3.0.0",
+        "eventemitter3": "^4.0.0",
         "follow-redirects": "^1.0.0",
         "requires-port": "^1.0.0"
+      },
+      "dependencies": {
+        "eventemitter3": {
+          "version": "4.0.7",
+          "resolved": "https://registry.npmjs.org/eventemitter3/-/eventemitter3-4.0.7.tgz",
+          "integrity": "sha512-8guHBZCwKnFhYdHr2ysuRWErTwhoN2X8XELRlrRwpmfeY2jjuUN4taQMsULKUVo1K4DvZl+0pgfyoysHxvmvEw=="
+        }
       }
     },
     "http-proxy-middleware": {
@@ -6600,7 +6621,8 @@
             },
             "ansi-regex": {
               "version": "2.1.1",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "aproba": {
               "version": "1.2.0",
@@ -6618,11 +6640,13 @@
             },
             "balanced-match": {
               "version": "1.0.0",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "brace-expansion": {
               "version": "1.1.11",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "balanced-match": "^1.0.0",
                 "concat-map": "0.0.1"
@@ -6635,15 +6659,18 @@
             },
             "code-point-at": {
               "version": "1.1.0",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "concat-map": {
               "version": "0.0.1",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "console-control-strings": {
               "version": "1.1.0",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "core-util-is": {
               "version": "1.0.2",
@@ -6746,7 +6773,8 @@
             },
             "inherits": {
               "version": "2.0.3",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "ini": {
               "version": "1.3.5",
@@ -6756,6 +6784,7 @@
             "is-fullwidth-code-point": {
               "version": "1.0.0",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "number-is-nan": "^1.0.0"
               }
@@ -6768,17 +6797,20 @@
             "minimatch": {
               "version": "3.0.4",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "brace-expansion": "^1.1.7"
               }
             },
             "minimist": {
               "version": "0.0.8",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "minipass": {
               "version": "2.3.5",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "safe-buffer": "^5.1.2",
                 "yallist": "^3.0.0"
@@ -6795,6 +6827,7 @@
             "mkdirp": {
               "version": "0.5.1",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "minimist": "0.0.8"
               }
@@ -6867,7 +6900,8 @@
             },
             "number-is-nan": {
               "version": "1.0.1",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "object-assign": {
               "version": "4.1.1",
@@ -6877,6 +6911,7 @@
             "once": {
               "version": "1.4.0",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "wrappy": "1"
               }
@@ -6952,7 +6987,8 @@
             },
             "safe-buffer": {
               "version": "5.1.2",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "safer-buffer": {
               "version": "2.1.2",
@@ -6982,6 +7018,7 @@
             "string-width": {
               "version": "1.0.2",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "code-point-at": "^1.0.0",
                 "is-fullwidth-code-point": "^1.0.0",
@@ -6999,6 +7036,7 @@
             "strip-ansi": {
               "version": "3.0.1",
               "bundled": true,
+              "optional": true,
               "requires": {
                 "ansi-regex": "^2.0.0"
               }
@@ -7037,11 +7075,13 @@
             },
             "wrappy": {
               "version": "1.0.2",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             },
             "yallist": {
               "version": "3.0.3",
-              "bundled": true
+              "bundled": true,
+              "optional": true
             }
           }
         }