3.21.1
======
* Notify clients of pending modifier state changes [Rui; #748526]
* Add get_is_builtin_display_on() method [Florian; #765267]
* Fix 2-finger titlebar taps on wayland [Carlos; #764519]
* Merge clutter and cogl forks into mutter [Rui; #760439]
* Misc. bug fixes [Florian, Victor, Jonas; #765058, #765252, #765062]

Contributors:
  Jonas Ådahl, Emmanuele Bassi, Olivier Fourdan, Carlos Garnacho, Rui Matos,
  Florian Müllner, Victor Toso, Rico Tzschichholz

Translations:
  GNOME Translation Robot [ja, gd]