[Actions] Bump dart-lang/setup-dart from 1.6.2 to 1.6.3 (#3)

Bumps [dart-lang/setup-dart](https://github.com/dart-lang/setup-dart) from 1.6.2 to 1.6.3.
- [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@v1.6.2...v1.6.3)

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

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

.github/workflows/build-docs.yml

@@ -17,7 +17,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Setup Dart
-      uses: dart-lang/[email protected].2
+      uses: dart-lang/[email protected].3
 
     - name: Install dependencies
       run: dart pub get

.github/workflows/tests.yml

@@ -20,7 +20,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Setup Dart
-      uses: dart-lang/[email protected].2
+      uses: dart-lang/[email protected].3
 
     - name: Install dependencies
       run: dart pub get