Update dependency ember-data to v3.28.6

Author: renovate-bot

package.json

@@ -86,7 +86,7 @@
     "ember-click-outside": "2.0.0",
     "ember-concurrency": "2.2.0",
     "ember-css-modules": "2.0.0",
-    "ember-data": "3.27.1",
+    "ember-data": "3.28.6",
     "ember-disable-prototype-extensions": "1.1.3",
     "ember-error-route": "0.2.0",
     "ember-event-helpers": "0.1.1",