chore(package): update ember-exam to version 4.0.0

Closes #1749

Author: greenkeeper[bot]

package.json

@@ -66,7 +66,7 @@
     "ember-data": "~2.18.0",
     "ember-disable-proxy-controllers": "^1.0.1",
     "ember-dragula": "1.9.3",
-    "ember-exam": "1.0.0",
+    "ember-exam": "4.0.0",
     "ember-export-application-global": "^2.0.0",
     "ember-font-awesome": "^3.0.5",
     "ember-i18n": "^5.0.2",