Prepare changelog for v0.12.8-rc.2

Author: dbkr

CHANGELOG.md

@@ -1,3 +1,10 @@
+Changes in [0.12.8-rc.2](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v0.12.8-rc.2) (2018-06-22)
+===============================================================================================================
+[Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v0.12.8-rc.1...v0.12.8-rc.2)
+
+ * slash got consumed in the consolidation
+   [\#1998](https://github.com/matrix-org/matrix-react-sdk/pull/1998)
+
 Changes in [0.12.8-rc.1](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v0.12.8-rc.1) (2018-06-21)
 ===============================================================================================================
 [Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v0.12.7...v0.12.8-rc.1)