Bump actions/checkout from 3.0.2 to 6.0.2

Bumps [actions/checkout](https://github.com/actions/checkout) from 3.0.2 to 6.0.2.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3.0.2...v6.0.2)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: 6.0.2
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/flutter.yml

@@ -11,7 +11,7 @@ jobs:
   analysis:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3.0.2
+      - uses: actions/checkout@v6.0.2
       - uses: actions/setup-java@v3.13.0
         with:
           java-version: 11
@@ -28,7 +28,7 @@ jobs:
   formatting:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3.0.2
+      - uses: actions/checkout@v6.0.2
       - uses: actions/setup-java@v3.13.0
         with:
           java-version: 11