Fix secrets name

Author: luispabon

.github/workflows/build-and-push-image.yaml

@@ -22,8 +22,8 @@ jobs:
       - name: Login to DockerHub
         uses: docker/login-action@v1
         with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_TOKEN }}
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_TOKEN }}
 
       - name: Build and push
         id: docker_build