message: Prepare changelog for v1.0.4
diff: +Changes in [1.0.4](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v1.0.4) (2019-03-18)
  +===================================================================================================
  +[Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v1.0.4-rc.1...v1.0.4)
  +
  + * No changes since rc.1
  +
  Changes in [1.0.4-rc.1](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v1.0.4-rc.1) (2019-03-13)
  =============================================================================================================
  [Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v1.0.3...v1.0.4-rc.1)
  