fix(package): update mocha to version 6.1.2

Closes #38

Author: greenkeeper[bot]

package.json

@@ -34,7 +34,7 @@
     "ember-cli-babel": "^6.8.2",
     "jquery": "^3.3.1",
     "jsdom": "^11.10.0",
-    "mocha": "^5.1.1",
+    "mocha": "^6.1.2",
     "request": "^2.85.0",
     "rsvp": "^4.7.0"
   },