Prepare changelog for v0.10.4

Author: dbkr

CHANGELOG.md

@@ -1,3 +1,9 @@
+Changes in [0.10.4](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v0.10.4) (2017-09-20)
+=====================================================================================================
+[Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v0.10.4-rc.1...v0.10.4)
+
+ * No changes
+
 Changes in [0.10.4-rc.1](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v0.10.4-rc.1) (2017-09-19)
 ===============================================================================================================
 [Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v0.10.3...v0.10.4-rc.1)