add link for gitolite

roadmap/2021.md

@@ -147,7 +147,7 @@ take longer to complete.
  * [ ] retire old services:
    * [ ] SVN ([issue 17202](https://gitlab.torproject.org/tpo/tpa/team/-/issues/17202))
    * [ ] fpcentral ([issue 40009](https://gitlab.torproject.org/tpo/tpa/team/-/issues/40009))
-   * [ ] establish plan for gitolite/gitweb retirement
+   * [ ] establish plan for gitolite/gitweb retirement ([issue 36](https://gitlab.torproject.org/tpo/tpa/gitlab/-/issues/36))
  * [ ] improve sysadmin code base
    * [ ] avoid YOLO commits in Puppet (possibly: server-side linting, CI)
    * [ ] publish our Puppet repository ([ticket 29387](https://gitlab.torproject.org/tpo/tpa/team/-/issues/29387))