Update UPDATING.md

UPDATING.md

@@ -34,6 +34,7 @@ assists people when migrating to a new version.
 
 ### Breaking Changes
 
+- [24262](https://github.com/apache/superset/pull/24262): Enabled `TALISMAN_ENABLED` flag by default and provided stricter default Content Security Policy
 - [24415](https://github.com/apache/superset/pull/24415): Removed the obsolete Druid NoSQL REGEX operator.
 - [24423](https://github.com/apache/superset/pull/24423): Removed deprecated APIs `/superset/slice_json/...`, `/superset/annotation_json/...`
 - [24400](https://github.com/apache/superset/pull/24400): Removed deprecated APIs `/superset/recent_activity/...`, `/superset/fave_dashboards_by_username/...`, `/superset/fave_dashboards/...`, `/superset/created_dashboards/...`, `/superset/user_slices/`, `/superset/created_slices/...`, `/superset/fave_slices/...`, `/superset/favstar/...`,