Bump gradle/actions from 4 to 6

Bumps [gradle/actions](https://github.com/gradle/actions) from 4 to 6.
- [Release notes](https://github.com/gradle/actions/releases)
- [Commits](https://github.com/gradle/actions/compare/v4...v6)

---
updated-dependencies:
- dependency-name: gradle/actions
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/ci.yml

@@ -19,7 +19,7 @@ jobs:
         with:
           distribution: temurin
           java-version: "21"
-      - uses: gradle/actions/setup-gradle@v4
+      - uses: gradle/actions/setup-gradle@v6
       - name: Verify Docker for MySQL integration tests
         run: docker info
       - name: Validate production Compose