Merge pull request #9062 from Turbo87/dep-workflow

Remove obsolete `ember-cli-deprecation-workflow` addon

Author: Turbo87

config/deprecation-workflow.js

@@ -86,7 +86,6 @@
     "ember-cli-code-coverage": "3.0.0",
     "ember-cli-dependency-checker": "3.3.2",
     "ember-cli-dependency-lint": "2.0.1",
-    "ember-cli-deprecation-workflow": "2.2.0",
     "ember-cli-head": "2.0.0",
     "ember-cli-htmlbars": "6.3.0",
     "ember-cli-inject-live-reload": "2.1.0",