message: Prepare changelog for v0.12.6-rc.1
diff: +Changes in [0.12.6-rc.1](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v0.12.6-rc.1) (2018-05-24)
  +===============================================================================================================
  +[Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v0.12.5...v0.12.6-rc.1)
  +
  + * Add a "reload widget" button.
  + [\#1920](https://github.com/matrix-org/matrix-react-sdk/pull/1920)
  + * Make devTools styling more consistent and easier to edit event data.
  + [\#1923](https://github.com/matrix-org/matrix-react-sdk/pull/1923)
  + * Update from Weblate.
  + [\#1930](https://github.com/matrix-org/matrix-react-sdk/pull/1930)
  + * Cookie bar update
  + [\#1929](https://github.com/matrix-org/matrix-react-sdk/pull/1929)
  + * Message for leaving server notices room
  + [\#1928](https://github.com/matrix-org/matrix-react-sdk/pull/1928)
  + * More thorough check of IM URL validity.
  + [\#1927](https://github.com/matrix-org/matrix-react-sdk/pull/1927)
  + * Add usage data link to cookie bar
  + [\#1926](https://github.com/matrix-org/matrix-react-sdk/pull/1926)
  + * Change wording and appearance of Deactivate Account dialog
  + [\#1925](https://github.com/matrix-org/matrix-react-sdk/pull/1925)
  + * fix membership list ordering when presence is disabled.
  + [\#1924](https://github.com/matrix-org/matrix-react-sdk/pull/1924)
  + * Implement erasure option upon deactivation
  + [\#1922](https://github.com/matrix-org/matrix-react-sdk/pull/1922)
  + * Add cookie warning to widget warning (AppPermission)
  + [\#1921](https://github.com/matrix-org/matrix-react-sdk/pull/1921)
  + * Terms and Conditions dialog
  + [\#1919](https://github.com/matrix-org/matrix-react-sdk/pull/1919)
  + * improve privileged section users in room settings
  + [\#1902](https://github.com/matrix-org/matrix-react-sdk/pull/1902)
  + * Space between sentences in 'leave room' warning
  + [\#1918](https://github.com/matrix-org/matrix-react-sdk/pull/1918)
  + * Specify valid address types to "Start a chat" dialog
  + [\#1908](https://github.com/matrix-org/matrix-react-sdk/pull/1908)
  + * Implement opt-in analytics with cookie bar
  + [\#1906](https://github.com/matrix-org/matrix-react-sdk/pull/1906)
  + * Fix vector-im/riot-web#6523 Emoji rendering destroys paragraphs
  + [\#1910](https://github.com/matrix-org/matrix-react-sdk/pull/1910)
  +
  Changes in [0.12.5](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v0.12.5) (2018-05-17)
  =====================================================================================================
  [Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v0.12.4...v0.12.5)
  