Bump docker/build-push-action from 6.7.0 to 6.9.0

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 6.7.0 to 6.9.0.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v6.7.0...v6.9.0)

---
updated-dependencies:
- dependency-name: docker/build-push-action
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/installation-action.yml

@@ -54,7 +54,7 @@ jobs:
          with:
            driver-opts: network=host
        - name: Build Docker image
-         uses: docker/build-push-action@v6.7.0
+         uses: docker/build-push-action@v6.9.0
          with:
            context: .
            file: ./tests/Dockerfile.rpi3-installation
@@ -93,7 +93,7 @@ jobs:
          with:
            driver-opts: network=host
        - name: Build Docker image
-         uses: docker/build-push-action@v6.7.0
+         uses: docker/build-push-action@v6.9.0
          with:
            context: .
            file: ./tests/Dockerfile.rpi3-64-installation