Update CHANGELOG.md

CHANGELOG.md

 # 6.2.0 (unreleased)
 
+# 6.1.1 (2019-04-05)
+
+ ### Bug Fixes
+  * **Alerting**: Notification channel http api fixes. [#16379](https://github.com/grafana/grafana/pull/16379), [@marefr](https://github.com/marefr)
+  * **Graphite**: Editing graphite query function now works again. [#16390](https://github.com/grafana/grafana/pull/16390), [@torkelo](https://github.com/torkelo)
+  * **Playlist**: Kiosk & auto fit panels modes are working normally again . [#16403](https://github.com/grafana/grafana/pull/16403), [@torkelo](https://github.com/torkelo)
+  * **QueryEditors**: Toggle edit mode now always work on slower computers. [#16394](https://github.com/grafana/grafana/pull/16394), [@seanlaff](https://github.com/seanlaff)
+
 # 6.1.0 (2019-04-03)
 
 ### Bug Fixes