[ci] automatically import new jupyterhub image into docker

.gitlab-ci.yml

@@ -24,5 +24,6 @@ deploy ubuntu:
     - podman tag "${image_name}/jupyterhub" "${image_name}/jupyterhub:$calver"
     - podman push "${image_name}/jupyterhub:$calver"
     - podman image rm "${image_name}/jupyterhub:$calver"
+    - docker pull "${image_name}/jupyterhub:$calver"
   after_script:
     - podman logout "${CI_REGISTRY}"