Build(deps-dev): Bump ember-cli from 3.9.0 to 3.12.0

Bumps [ember-cli](https://github.com/ember-cli/ember-cli) from 3.9.0 to 3.12.0.
- [Release notes](https://github.com/ember-cli/ember-cli/releases)
- [Changelog](https://github.com/ember-cli/ember-cli/blob/master/CHANGELOG.md)
- [Commits](ember-cli/ember-cli@v3.9.0...v3.12.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Author: dependabot-preview[bot]

package.json

@@ -52,7 +52,7 @@
     "@types/ember__test-helpers": "^0.7.8",
     "@types/qunit": "^2.5.4",
     "@types/rsvp": "^4.0.2",
-    "ember-cli": "~3.9.0",
+    "ember-cli": "~3.12.0",
     "ember-cli-dependency-checker": "^3.2.0",
     "ember-cli-eslint": "^4.2.3",
     "ember-cli-htmlbars": "^3.1.0",