changelog: add notes about closing #11977

[skip ci]

CHANGELOG.md

@@ -15,6 +15,7 @@
 * **Cloudwatch**: AWS/Connect metrics and dimensions [#13970](https://github.com/grafana/grafana/pull/13970), thx [@zcoffy](https://github.com/zcoffy)
 * **Postgres**: Add delta window function to postgres query builder [#13925](https://github.com/grafana/grafana/issues/13925), thx [svenklemm](https://github.com/svenklemm)
 * **Elasticsearch**: Fix switching to/from es raw document metric query [#6367](https://github.com/grafana/grafana/issues/6367)
+* **Elasticsearch**: Fix deprecation warning about terms aggregation order key in Elasticsearch 6.x [#11977](https://github.com/grafana/grafana/issues/11977)
 * **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)
 * **Datasource Proxy**: Keep trailing slash for datasource proxy requests [#13326](https://github.com/grafana/grafana/pull/13326), thx [@ryantxu](https://github.com/ryantxu)
 * **DingDing**: Can't receive DingDing alert when alert is triggered [#13723](https://github.com/grafana/grafana/issues/13723), thx [@Yukinoshita-Yukino](https://github.com/Yukinoshita-Yukino)