fix: auth

Author: fmenezes

.github/workflows/docker.yaml

@@ -29,7 +29,7 @@ jobs:
       - name: Login to Docker Hub
         uses: docker/login-action@343f7c4344506bcbf9b4de18042ae17996df046d
         with:
-          username: "${{ secrets.DOCKERHUB_USER }}"
+          username: "${{ secrets.DOCKERHUB_USERNAME }}"
           password: "${{ secrets.DOCKERHUB_SECRET }}"
       - name: Build and push image to dockerhub staging registry
         uses: docker/build-push-action@14487ce63c7a62a4a324b0bfb37086795e31c6c1