chore(package): update @ember/optional-features to version 1.1.0

Closes #38

Author: greenkeeper[bot]

package.json

@@ -21,7 +21,7 @@
     "test:all": "ember try:each"
   },
   "devDependencies": {
-    "@ember/optional-features": "^0.6.3",
+    "@ember/optional-features": "^1.1.0",
     "broccoli-asset-rev": "^2.7.0",
     "ember-cli": "~3.6.0",
     "ember-cli-babel": "^7.1.2",