message: Prepare changelog for v0.8.7
diff: +Changes in [0.8.7](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v0.8.7) (2017-04-12)
  +===================================================================================================
  +[Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v0.8.7-rc.4...v0.8.7)
  +
  + * No changes
  +
  Changes in [0.8.7-rc.4](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v0.8.7-rc.4) (2017-04-11)
  =============================================================================================================
  [Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v0.8.7-rc.3...v0.8.7-rc.4)
  