fix(package): update ember-cli-babel to version 6.6.0

Closes #17

Author: greenkeeper[bot]

package.json

@@ -25,7 +25,7 @@
     "broccoli-funnel": "^1.1.0",
     "broccoli-merge-trees": "^1.2.1",
     "broccoli-persistent-filter": "^1.2.12",
-    "ember-cli-babel": "^5.1.7",
+    "ember-cli-babel": "^6.6.0",
     "glob": "^7.1.1",
     "postcss": "^5.2.8"
   },