[mutter] Bump version to 3.21.1

[Florian Müllner <fmuellner src gnome org>]

commit 4a26daea017e460072c262278ae127b293adf9e0
Author: Florian Müllner <fmuellner gnome org>
Date:   Wed Apr 27 21:13:00 2016 +0200

    Bump version to 3.21.1
    
    Update NEWS.

 NEWS         |   15 +++++++++++++++
 configure.ac |    2 +-
 2 files changed, 16 insertions(+), 1 deletions(-)
---
diff --git a/NEWS b/NEWS
index 52c5ee8..224b026 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,18 @@
+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]
+
 3.20.1
 ======
 * Constrain window move/resizes on wayland as on X11 [Rui; #748819]
diff --git a/configure.ac b/configure.ac
index 07dc3e9..a647fa3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,7 +1,7 @@
 AC_PREREQ(2.62)
 
 m4_define([mutter_major_version], [3])
-m4_define([mutter_minor_version], [20])
+m4_define([mutter_minor_version], [21])
 m4_define([mutter_micro_version], [1])
 
 m4_define([mutter_version],