Bump dart-lang/setup-dart from 1.6.4 to 1.6.5

Bumps [dart-lang/setup-dart](https://github.com/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](dart-lang/setup-dart@f0ead98...0a8a0fc)

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

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

.github/workflows/validate.yml

@@ -21,7 +21,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332
-      - uses: dart-lang/setup-dart@f0ead981b4d9a35b37f30d36160575d60931ec30
+      - uses: dart-lang/setup-dart@0a8a0fc875eb934c15d08629302413c671d3f672
         with:
           sdk: ${{ matrix.sdk }}