chore: Update CHANGELOG

Signed-off-by: Sebastian Fey <[email protected]>

Author: seyfeb

CHANGELOG.md

@@ -35,6 +35,8 @@
   [#1871](https://github.com./nextcloud/cookbook/pull/1871) @seyfeb
 - Load config at app loading only once and do not rewrite complete config
   [#1892](https://github.com./nextcloud/cookbook/pull/1892) @christianlupus
+- Add filter for timestamps to output canonical ISO8601 timestamps in the form of YYYY-MM-DDTHH:mm:ss±hh:mm See issue [#1543](https://github.com./nextcloud/cookbook/issues/1543)
+  [#1903](https://github.com./nextcloud/cookbook/pull/1903) @seyfeb
 
 ### Maintenance
 - Fix URL of Transifex after upstream subdomain change