chore(deps-dev): bump ember-source from 5.12.0 to 6.4.0

Bumps [ember-source](https://github.com/emberjs/ember.js) from 5.12.0 to 6.4.0.
- [Release notes](https://github.com/emberjs/ember.js/releases)
- [Changelog](https://github.com/emberjs/ember.js/blob/main/CHANGELOG.md)
- [Commits](https://github.com/emberjs/ember.js/commits)

---
updated-dependencies:
- dependency-name: ember-source
  dependency-version: 6.4.0
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

package.json

@@ -55,7 +55,7 @@
     "ember-prism": "~0.13.0",
     "ember-qunit": "~5.1.5",
     "ember-resolver": "~9.0.1",
-    "ember-source": "~5.12.0",
+    "ember-source": "~6.4.0",
     "ember-source-channel-url": "~3.0.0",
     "ember-template-lint": "~5.13.0",
     "ember-try": "~2.0.0",