Add caution about repo cleanup to repository storage move API

doc/api/project_repository_storage_moves.md

@@ -194,6 +194,14 @@ Example response:
 
 ## Schedule a repository storage move for a project
 
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/34119) in GitLab 13.1.
+> - [Introduced](https://gitlab.com/gitlab-org/gitaly/-/issues/2618) in GitLab 13.3, original repository is automatically removed after successful move and integrity check.
+
+CAUTION: **Caution:**
+Before GitLab 13.3, a repository move worked more like a repository copy as the
+original repository was not deleted from the original storage disk location and
+had to be manually cleaned up.
+
 ```plaintext
 POST /projects/:project_id/repository_storage_moves
 ```