Bump the github-actions group with 2 updates (dart-lang/markdown#617)

Bumps the github-actions group with 2 updates: [actions/checkout](https://github.com/actions/checkout) and [dart-lang/setup-dart](https://github.com/dart-lang/setup-dart).


Updates `actions/checkout` from 4.1.6 to 4.1.7
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/a5ac7e51b41094c92402da3b24376905380afc29...692973e3d937129bcbf40652eb9f2f61becf3332)

Updates `dart-lang/setup-dart` from 1.6.4 to 1.6.5
- [Release notes](https://github.com/dart-lang/setup-dart/releases)
- [Changelog](https://github.com/dart-lang/setup-dart/blob/main/CHANGELOG.md)
- [Commits](https://github.com/dart-lang/setup-dart/compare/f0ead981b4d9a35b37f30d36160575d60931ec30...0a8a0fc875eb934c15d08629302413c671d3f672)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: github-actions
- dependency-name: dart-lang/setup-dart
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: github-actions
...

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