Bump docker/build-push-action from 5 to 6 (#398)

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 5 to 6.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v5...v6)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/test-docker-image-build.yml

@@ -18,7 +18,7 @@ jobs:
         run: echo "image-tag=ts-bridge:test" >> $GITHUB_ENV
 
       - name: Build Docker Image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           push: false
           tags: ${{ env.image-tag }}