Removed printing Docker username

Had added it initially for testing purposes.
Can remove now so it doesn't expose any sensitive info.

.github/workflows/image_build_push.yml

@@ -31,7 +31,6 @@ jobs:
     - uses: actions/checkout@v2
     - name: docker login
       run: | # log into docker hub account
-        echo "Docker user name: " $DOCKER_USER
         docker login -u $DOCKER_USER -p $DOCKER_PASSWORD
 
     - name: Get current date # get the date of the build