Add version to "Fix effective access level of group members"

doc/api/members.md

@@ -90,7 +90,9 @@ Example response:
 
 Gets a list of group or project members viewable by the authenticated user, including inherited members and permissions through ancestor groups.
 
-If a user is a member of this group or project and also of one or more ancestor groups, only its membership with the highest `access_level` is returned.
+If a user is a member of this group or project and also of one or more ancestor groups,
+only its membership with the highest `access_level` is returned.
+([Improved](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/56677)] in GitLab 13.11.)
 This represents the effective permission of the user.
 
 This function takes pagination parameters `page` and `per_page` to restrict the list of users.