Update CHANGELOG.md

Update [Unreleased]: v0.6.2...master

CHANGELOG.md

@@ -167,6 +167,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Skip migrations when reinstalling missing code - [#76](https://github.com/owncloud/market/issues/76)
 - Reset overwritten core css styles - [#73](https://github.com/owncloud/market/issues/73)
 
+[Unreleased]: https://github.com/owncloud/market/compare/v0.6.2...master
 [0.6.2]: https://github.com/owncloud/market/compare/v0.6.1...v0.6.2
 [0.6.1]: https://github.com/owncloud/market/compare/v0.6.0...v0.6.1
 [0.6.0]: https://github.com/owncloud/market/compare/v0.5.1...v0.6.0