Bump docker/build-push-action from 5 to 6 (#2858)

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] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/docker-image-builds.yml

@@ -59,7 +59,7 @@ jobs:
 
       # Finally, build and push the images
       - name: Build image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: ${{ matrix.context }}
           platforms: linux/amd64,linux/arm,linux/arm64

.github/workflows/docker-transmission-builds.yml

@@ -46,7 +46,7 @@ jobs:
 
       # Finally, build and push the image
       - name: Build image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: upstream
           platforms: linux/amd64,linux/arm,linux/arm64