Bump docker/build-push-action from 5 to 6 (#2207)

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](https://github.com/docker/build-push-action/compare/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>

.github/workflows/docker.yml

@@ -59,7 +59,7 @@ jobs:
           platforms: linux/amd64,linux/arm64
 
       - name: Build
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           push: false
           load: true
@@ -72,7 +72,7 @@ jobs:
 
       - name: Build and push
         if: ${{ (github.event_name != 'pull_request') && (github.repository == 'cowrie/cowrie') }}
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           file: docker/Dockerfile
           platforms: linux/amd64,linux/arm64