chore(package): update grunt-modernizr to version 2.1.1

Closes #26

package.json

@@ -34,7 +34,7 @@
     "grunt-contrib-watch": "~1.1.0",
     "grunt-jekyll": "~1.0.0",
     "grunt-contrib-connect": "~2.0.0",
-    "grunt-modernizr": "~1.0.2",
+    "grunt-modernizr": "~2.1.1",
     "grunt-svgmin": "~5.0.0"
   }
 }