Bump ember-cli from 3.7.1 to 3.8.1

Bumps [ember-cli](https://github.com/ember-cli/ember-cli) from 3.7.1 to 3.8.1.
- [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@v3.7.1...v3.8.1)

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

Author: dependabot-support

package.json

@@ -19,7 +19,7 @@
   "devDependencies": {
     "@ember/optional-features": "^0.7.0",
     "broccoli-asset-rev": "^3.0.0",
-    "ember-cli": "~3.7.1",
+    "ember-cli": "~3.8.1",
     "ember-cli-babel": "^7.4.2",
     "ember-cli-dependency-checker": "^3.1.0",
     "ember-cli-deploy": "^1.0.2",