[docs] Added changelog for 1.1.1 release

Author: pandafy

CHANGES.rst

@@ -6,6 +6,16 @@ Version 1.2.0 [Unreleased]
 
 Work in progress.
 
+Version 1.1.1 [2025-01-31]
+--------------------------
+
+Bugfixes
+~~~~~~~~
+
+- Fixed `unnecessary triggering of
+  "update_superuser_notification_settings" celery task
+  <https://github.com/openwisp/openwisp-notifications/issues/283>`_.
+
 Version 1.1.0 [2024-11-20]
 --------------------------