Merge branch 'docs-update-project-release' into 'master'

Update Subgroup Project Release Information

See merge request gitlab-org/gitlab!76924

doc/user/project/releases/index.md

@@ -344,6 +344,11 @@ Here is an example of milestones with no releases, one release, and two releases
 
 ![Milestones with and without Release associations](img/milestone_list_with_releases_v12_5.png)
 
+NOTE:
+A subgroup's project releases cannot be associated with a supergroup's milestone. To learn
+more, read issue #328054,
+[Releases cannot be associated with a supergroup milestone](https://gitlab.com/gitlab-org/gitlab/-/issues/328054).
+
 ## Get notified when a release is created
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/26001) in GitLab 12.4.