try another way of writing registries.yaml

ansible/roles/pre-configure/templates/registries.yaml

@@ -2,9 +2,11 @@
 mirrors:
   docker.io:
     endpoint:
-      - "https://{{ docker_mirror.endpoint }}"
+      # Hardcoded, should be fixed before merging
+      - "open.greenhost.net/openappstack/dependency_proxy/containers"
 configs:
-  "{{ docker_mirror.endpoint }}":
+  # TODO: Hardcoded because GitLab does not give us the right path
+  "open.greenhost.net":
     auth:
       username: "{{ docker_mirror.username }}"
       password: "{{ docker_mirror.password }}"