changelog: add notes about closing #12749

[skip ci]

CHANGELOG.md

@@ -17,6 +17,7 @@
 * **Variables**: Skip unneeded extra query request when de-selecting variable values used for repeated panels [#8186](https://github.com/grafana/grafana/issues/8186), thx [@mtanda](https://github.com/mtanda)
 * **Postgres/MySQL/MSSQL**: Use floor rounding in $__timeGroup macro function [#12460](https://github.com/grafana/grafana/issues/12460), thx [@svenklemm](https://github.com/svenklemm)
 * **Postgres/MySQL/MSSQL**: Use metric column as prefix when returning multiple value columns [#12727](https://github.com/grafana/grafana/issues/12727), thx [@svenklemm](https://github.com/svenklemm)
+* **Postgres/MySQL/MSSQL**: New $__timeGroupAlias macro. Postgres $__timeGroup no longer automatically adds time column alias [#12749](https://github.com/grafana/grafana/issues/12749), thx [@svenklemm](https://github.com/svenklemm)
 * **Postgres/MySQL/MSSQL**: Escape single quotes in variables [#12785](https://github.com/grafana/grafana/issues/12785), thx [@eMerzh](https://github.com/eMerzh)
 * **MySQL/MSSQL**: Use datetime format instead of epoch for $__timeFilter, $__timeFrom and $__timeTo macros [#11618](https://github.com/grafana/grafana/issues/11618) [#11619](https://github.com/grafana/grafana/issues/11619), thx [@AustinWinstanley](https://github.com/AustinWinstanley)
 * **Postgres**: Escape ssl mode parameter in connectionstring [#12644](https://github.com/grafana/grafana/issues/12644), thx [@yogyrahmawan](https://github.com/yogyrahmawan)
@@ -36,6 +37,10 @@
 * **Graph**: Option to hide series from tooltip [#3341](https://github.com/grafana/grafana/issues/3341), thx [@mtanda](https://github.com/mtanda)
 * **UI**: Fix iOS home screen "app" icon and Windows 10 app experience [#12752](https://github.com/grafana/grafana/issues/12752), thx [@andig](https://github.com/andig)
 
+### Breaking changes
+
+* Postgres datasource no longer automatically adds time column alias when using the $__timeGroup alias. However, there's code in place which should make this change backward compatible and shouldn't create any issues.
+
 # 5.2.2 (2018-07-25)
 
 ### Minor