Bump ember-cli-stylelint from 2.2.0 to 4.0.0 (#1311)

Bumps [ember-cli-stylelint](https://github.com/billybonks/ember-cli-stylelint) from 2.2.0 to 4.0.0.
- [Release notes](https://github.com/billybonks/ember-cli-stylelint/releases)
- [Commits](billybonks/ember-cli-stylelint@2.2.0...4.0.0)

---
updated-dependencies:
- dependency-name: ember-cli-stylelint
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

package.json

@@ -142,7 +142,7 @@
     "ember-cli-showdown": "^4.4.4",
     "ember-cli-sri": "^2.1.1",
     "ember-cli-string-helpers": "^5.0.0",
-    "ember-cli-stylelint": "^2.1.0",
+    "ember-cli-stylelint": "^4.0.0",
     "ember-cli-terser": "^4.0.1",
     "ember-cli-test-loader": "^2.2.0",
     "ember-cli-typescript": "^4.1.0",