chore(deps): update docker/build-push-action digest to ee4ca42 (#289)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/docker-image.yml

@@ -21,7 +21,7 @@ jobs:
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: ${{ github.ref == 'refs/heads/main' && 'Build and Push' || 'Test Build' }}
-        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6
+        uses: docker/build-push-action@ee4ca427a2f43b6a16632044ca514c076267da23 # v6
         with:
             push: ${{ github.ref == 'refs/heads/main' }}
             tags: ghcr.io/biaw/ookla-speedtest-server:latest