fix(dev): Fix ember-cli version (#3025)

The updated version accidentally ended up in regular dependencies rather than dev dependencies, leading to conflicting versions.

Author: lobsterkatie

packages/ember/package.json

@@ -37,7 +37,6 @@
     "@sentry/types": "5.27.2",
     "@sentry/utils": "5.27.2",
     "ember-auto-import": "^1.6.0",
-    "ember-cli": "^3.21.2",
     "ember-cli-babel": "^7.20.5",
     "ember-cli-htmlbars": "^5.1.2",
     "ember-cli-typescript": "^3.1.4",
@@ -55,7 +54,7 @@
     "@types/rsvp": "^4.0.3",
     "babel-eslint": "^10.1.0",
     "broccoli-asset-rev": "^3.0.0",
-    "ember-cli": "^3.19.0",
+    "ember-cli": "^3.21.2",
     "ember-cli-dependency-checker": "^3.2.0",
     "ember-cli-inject-live-reload": "^2.0.2",
     "ember-cli-sri": "^2.1.1",