Bump docker/build-push-action from 3 to 6 (#9)

Author: dependabot[bot]

.github/workflows/dockerimage.yml

@@ -23,7 +23,7 @@ jobs:
 
     # https://github.com/marketplace/actions/build-and-push-docker-images
     - name: Build the Docker image
-      uses: docker/build-push-action@v3
+      uses: docker/build-push-action@v6
       with:
         context: .
         tags: macbre/curl-http3