Prepare changelog for v1.2.2

Author: RiotRobot

CHANGELOG.md

@@ -1,3 +1,9 @@
+Changes in [1.2.2](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v1.2.2) (2019-06-19)
+===================================================================================================
+[Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v1.2.2-rc.2...v1.2.2)
+
+No changes since rc.2
+
 Changes in [1.2.2-rc.2](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v1.2.2-rc.2) (2019-06-18)
 =============================================================================================================
 [Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v1.2.2-rc.1...v1.2.2-rc.2)