chore(deps): update dependency ember-source to v3.28.8

Author: renovate-bot

package.json

@@ -71,7 +71,7 @@
     "ember-page-title": "^6.2.2",
     "ember-qunit": "5.1.4",
     "ember-resolver": "8.0.2",
-    "ember-source": "3.28.0",
+    "ember-source": "3.28.8",
     "ember-source-channel-url": "3.0.0",
     "ember-template-lint": "^3.6.0",
     "ember-truth-helpers": "3.0.0",