add tag for docker image

Author: mjoppich

.circleci/config.yml

@@ -9,7 +9,7 @@ jobs:
     # Specify the execution environment. You can specify an image from Dockerhub or use one of our Convenience Images from CircleCI's Developer Hub.
     # See: https://circleci.com/docs/2.0/configuration-reference/#docker-machine-macos-windows-executor
     docker:
-      - image: mjoppich/rbase_git
+      - image: mjoppich/rbase_git:452
     resource_class: medium
     # Add steps to the job
     # See: https://circleci.com/docs/2.0/configuration-reference/#steps