fix(changelog): add info about merged PR's

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ### New Features
 * **Elasticsearch**: Support for pipeline aggregations Moving average and derivative, closes [#2715](https://github.com/grafana/grafana/issues/2715)
+* **Syslog**: Support for syslog logging, closes [#3161](https://github.com/grafana/grafana/pull/3161)
+* **Timepicker**: Always show refresh button even with refresh rate, closes [#3498](https://github.com/grafana/grafana/pull/3498)
 
 ### Bug Fixes
 * **metric editors**: Fix for clicking typeahead auto dropdown option, fixes [#3428](https://github.com/grafana/grafana/issues/3428)