build(deps): bump dart-lang/setup-dart from 1.3 to 1.4

Bumps [dart-lang/setup-dart](https://github.com/dart-lang/setup-dart) from 1.3 to 1.4.
- [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@v1.3...v1.4)

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

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

.github/workflows/run_ci.yml

@@ -19,7 +19,7 @@ jobs:
         dart: [stable, beta, dev]
     steps:
       - uses: actions/checkout@v2
-      - uses: dart-lang/setup-dart@v1.3
+      - uses: dart-lang/setup-dart@v1.4
         with:
           sdk: ${{ matrix.dart }}
       - run: dart --version