Fix retrieve token from dockerhub for docker-mods

There is a missing grep in the curl instruction to retrieve the token from DockerHub

root/docker-mods

@@ -101,6 +101,7 @@ for DOCKER_MOD in "${DOCKER_MODS[@]}"; do
     --silent \
     --header 'GET' \
     "${AUTH_URL}" \
+    | grep -m1 "token" \
     | awk -F'"' '{print $4}' \
   )"
   # Determine first and only layer of image