Prepare changelog for v2.1.0-rc.2

Author: RiotRobot

CHANGELOG.md

@@ -1,3 +1,9 @@
+Changes in [2.1.0-rc.2](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v2.1.0-rc.2) (2020-02-13)
+=============================================================================================================
+[Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v2.1.0-rc.1...v2.1.0-rc.2)
+
+ * Fix error in previous attempt to upgrade JS SDK 
+
 Changes in [2.1.0-rc.1](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v2.1.0-rc.1) (2020-02-13)
 =============================================================================================================
 [Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v2.0.0...v2.1.0-rc.1)