build(deps): bump subosito/flutter-action from 2.17.0 to 2.18.0 (#616)

Bumps [subosito/flutter-action](https://github.com/subosito/flutter-action) from 2.17.0 to 2.18.0.
- [Release notes](https://github.com/subosito/flutter-action/releases)
- [Commits](subosito/flutter-action@74af56c...f2c4f66)

---
updated-dependencies:
- dependency-name: subosito/flutter-action
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

.github/workflows/test.yaml

@@ -28,7 +28,7 @@ jobs:
           fetch-depth: 0
 
       - name: Install Flutter
-        uses: subosito/flutter-action@74af56c5ed2697ba4621264652728e8d217e53d3
+        uses: subosito/flutter-action@f2c4f6686ca8e8d6e6d0f28410eeef506ed66aff
         with:
           channel: 'stable'