Update CHANGELOG.md

CHANGELOG.md

@@ -8,6 +8,7 @@
 
 * **Datasource Proxy**: Keep trailing slash for datasource proxy requests [#13326](https://github.com/grafana/grafana/pull/13326), thx [@ryantxu](https://github.com/ryantxu)
 * **Elasticsearch**: Fix no limit size in terms aggregation for alerting queries [#13172](https://github.com/grafana/grafana/issues/13172), thx [@Yukinoshita-Yukino](https://github.com/Yukinoshita-Yukino)
+* **Units**: New clock time format, to format ms or second values as for example `01h:59m`, [#13635](https://github.com/grafana/grafana/issues/13635), thx [@franciscocpg](https://github.com/franciscocpg)
 
 ### Breaking changes