Add wiki page events fix to the Changelog

CHANGELOG

@@ -2,6 +2,7 @@ Please view this file on the master branch, on stable branches it's out of date.
 
 v 8.9.0 (unreleased)
   - Allow enabling wiki page events from Webhook management UI
+  - Fix wiki page events' webhook to point to the wiki repository
   - Allow forking projects with restricted visibility level
   - Improve note validation to prevent errors when creating invalid note via API
   - Redesign navigation for project pages