Bump docker/build-push-action from 5 to 6

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>

.github/workflows/docker.yml

@@ -73,7 +73,7 @@ jobs:
         password: ${{ secrets.DOCKER_PASSWORD }}
 
     - name: Build and push Docker image - (MAIN)
-      uses: docker/build-push-action@v5
+      uses: docker/build-push-action@v6
       if: success()
       env:
         DOCKER_BUILDKIT: 1
@@ -88,7 +88,7 @@ jobs:
         tags: ${{ env.REGISTRY }}/${{ env.OWNER }}/${{ env.REPO_NAME }}:${{ env.TAG == 'main' && 'latest' || env.TAG }}
 
     - name: Build and push Docker image - (DATE)
-      uses: docker/build-push-action@v5
+      uses: docker/build-push-action@v6
       if: ${{ github.event_name == 'schedule' || contains(github.ref, 'main') }}
       env:
         DOCKER_BUILDKIT: 1