Bump ember-template-lint from 2.1.0 to 2.4.0

Bumps [ember-template-lint](https://github.com/ember-template-lint/ember-template-lint) from 2.1.0 to 2.4.0.
- [Release notes](https://github.com/ember-template-lint/ember-template-lint/releases)
- [Changelog](https://github.com/ember-template-lint/ember-template-lint/blob/master/CHANGELOG.md)
- [Commits](ember-template-lint/ember-template-lint@v2.1.0...v2.4.0)

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

Author: dependabot-preview[bot]

package-lock.json

@@ -72,7 +72,7 @@
     "ember-promise-helpers": "^1.0.9",
     "ember-resolver": "^7.0.0",
     "ember-router-scroll": "^2.0.1",
-    "ember-template-lint": "^2.1.0",
+    "ember-template-lint": "^2.4.0",
     "ember-source": "~3.16.1",
     "ember-svg-jar": "^2.2.3",
     "ember-test-selectors": "^4.0.0",