updated Jenkinsfile

Jenkinsfile

@@ -57,7 +57,7 @@ pipeline {
             steps {
                 echo 'Cleanup...'
                 sh """
-                docker image prune -f
+                docker rmi `docker images | grep '<none>' | grep -v IMAGE | awk '{ print \$3 }' | xargs`
                 """
             }
         }