Bump docker/build-push-action from 5.3.0 to 6.4.0

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 5.3.0 to 6.4.0.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](https://github.com/docker/build-push-action/compare/v5.3.0...v6.4.0)

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

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

.github/workflows/update-test-ubuntu-git.yml

@@ -48,7 +48,7 @@ jobs:
 
       # Use `docker/build-push-action` to build (and optionally publish) the image. 
       - name: Build Docker Image (with optional Push)
-        uses: docker/build-push-action@v5.3.0
+        uses: docker/build-push-action@v6.4.0
         with:
           context: .
           file: images/test-ubuntu-git.Dockerfile