chore(deps): update docker/build-push-action action to v7

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@10e90e3645eae34f1e60eeb005ba3a3d33f178e8 # v6
+        uses: docker/build-push-action@d08e5c354a6adb9ed34480a06d141179aa583294 # v7
         with:
             push: ${{ github.ref == 'refs/heads/main' }}
             tags: ghcr.io/biaw/ookla-speedtest-server:latest