fix(package): update ember-cli-htmlbars to version 4.1.1

Closes #17

Author: greenkeeper[bot]

package.json

@@ -27,7 +27,7 @@
   "dependencies": {
     "coveralls": "^3.0.3",
     "ember-cli-babel": "^7.7.3",
-    "ember-cli-htmlbars": "^3.0.1"
+    "ember-cli-htmlbars": "^4.1.1"
   },
   "devDependencies": {
     "@ember/optional-features": "^0.7.0",