Bump subosito/flutter-action from 2.7.1 to 2.8.0 (#1127)

Bumps [subosito/flutter-action](https://github.com/subosito/flutter-action) from 2.7.1 to 2.8.0.
- [Release notes](https://github.com/subosito/flutter-action/releases)
- [Commits](subosito/flutter-action@1e6ee87...dbf1fa0)

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

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

.github/workflows/flutter-ci.yml

@@ -31,7 +31,7 @@ jobs:
         with:
           distribution: 'zulu' # See https://github.com/actions/setup-java#supported-distributions
           java-version: "12.x"
-      - uses: subosito/flutter-action@1e6ee87cb840500837bcd50a667fb28815d8e310
+      - uses: subosito/flutter-action@dbf1fa04f4d2e52c33185153d06cdb5443aa189d
         with:
           channel: ${{ matrix.flutter_version }}
       - run: dart --version