drop addon versions to maintain support for ember <3.12

package.json

@@ -29,8 +29,8 @@
   "dependencies": {
     "@html-next/vertical-collection": "^1.0.0",
     "ember-cli-babel": "^7.21.0",
-    "ember-cli-htmlbars": "^5.2.0",
-    "ember-cli-string-helpers": "^5.0.0",
+    "ember-cli-htmlbars": "^4.3.1",
+    "ember-cli-string-helpers": "^4.0.7",
     "ember-get-config": "^0.2.4",
     "ember-in-viewport": "^3.7.2",
     "ember-scrollable": "^1.0.2",

yarn.lock

@@ -3495,22 +3495,6 @@ broccoli-funnel@^3.0.2:
     path-posix "^1.0.0"
     walk-sync "^2.0.2"
 
-broccoli-funnel@^3.0.3:
-  version "3.0.3"
-  resolved "https://registry.yarnpkg.com/broccoli-funnel/-/broccoli-funnel-3.0.3.tgz#26fd42632471f67a91f4770d1987118087219937"
-  integrity sha512-LPzZ91BwStoHZXdXHQAJeYORl189OrRKM5NdIi86SDU9wZ4s/3lV1PRFOiobDT/jKM10voM7CDzfvicHbCYxAQ==
-  dependencies:
-    array-equal "^1.0.0"
-    blank-object "^1.0.1"
-    broccoli-plugin "^4.0.1"
-    debug "^4.1.1"
-    fast-ordered-set "^1.0.0"
-    fs-tree-diff "^2.0.1"
-    heimdalljs "^0.2.0"
-    minimatch "^3.0.0"
-    path-posix "^1.0.0"
-    walk-sync "^2.0.2"
-
 broccoli-kitchen-sink-helpers@^0.2.5:
   version "0.2.9"
   resolved "https://registry.yarnpkg.com/broccoli-kitchen-sink-helpers/-/broccoli-kitchen-sink-helpers-0.2.9.tgz#a5e0986ed8d76fb5984b68c3f0450d3a96e36ecc"
@@ -5554,7 +5538,7 @@ ember-cli-htmlbars@^4.2.3, ember-cli-htmlbars@^4.3.1:
     strip-bom "^4.0.0"
     walk-sync "^2.0.2"
 
-ember-cli-htmlbars@^5.1.1, ember-cli-htmlbars@^5.2.0:
+ember-cli-htmlbars@^5.1.1:
   version "5.2.0"
   resolved "https://registry.yarnpkg.com/ember-cli-htmlbars/-/ember-cli-htmlbars-5.2.0.tgz#5ceccd0d18163dd810dea29f6fd777d0baa01e23"
   integrity sha512-EdjuUc7sq9ve6sgsG59qIzOj4svWjgYhO/QEhuV1UbOQ3ATeqNPiD++bFeAGjUhravw9HPhQPPoHnMlAikqLIw==
@@ -5676,12 +5660,12 @@ ember-cli-sri@^2.1.1:
   dependencies:
     broccoli-sri-hash "^2.1.0"
 
-ember-cli-string-helpers@^5.0.0:
-  version "5.0.0"
-  resolved "https://registry.yarnpkg.com/ember-cli-string-helpers/-/ember-cli-string-helpers-5.0.0.tgz#b1e08ec3ca1c9a457f9fd9aafff60b5939fbf91d"
-  integrity sha512-PodD3Uf7BkOXIu95E6cWEC0ERroTiUOAwOr828Vb+fPFtV7WYNSC27C9Ds1ggCyyRqnXmpS0JSqCTN1gPZfkWQ==
+ember-cli-string-helpers@^4.0.7:
+  version "4.0.7"
+  resolved "https://registry.yarnpkg.com/ember-cli-string-helpers/-/ember-cli-string-helpers-4.0.7.tgz#181e36f5cd6e99a211cca0a5e2d90381c4658f5f"
+  integrity sha512-jG99vlO4wzHk0jQcl4wFCJfaEsXBWITXsETuoIPd0r5hNMuhKUJ0CA0qif1Lr7Udwl52ay2D3VLqEmZZYdvSjw==
   dependencies:
-    broccoli-funnel "^3.0.3"
+    broccoli-funnel "^2.0.2"
     ember-cli-babel "^7.7.3"
 
 ember-cli-string-utils@^1.0.0, ember-cli-string-utils@^1.1.0: