Fixed Dockerhub secrets name

Author: kerero

.github/workflows/docker-publish.yml

@@ -48,7 +48,7 @@ jobs:
         uses: docker/login-action@v1
         with:
           registry: ${{ env.REGISTRY }}
-          username: ${{ github.DOCKERHUB_USER }}
+          username: ${{ secrets.DOCKERHUB_USER }}
           password: ${{ secrets.DOCKERHUB_PASS }}
 
       # Extract metadata (tags, labels) for Docker