[mutter] Bump version to 3.21.3

[Florian Müllner <fmuellner src gnome org>]

commit 2f74ecd469b41d9c81c2c19879de64ebef46e594
Author: Florian Müllner <fmuellner gnome org>
Date:   Tue Jun 21 21:04:52 2016 +0200

    Bump version to 3.21.3
    
    Update NEWS.

 NEWS         |   15 +++++++++++++++
 configure.ac |    2 +-
 2 files changed, 16 insertions(+), 1 deletions(-)
---
diff --git a/NEWS b/NEWS
index 64e2e78..56f212b 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,18 @@
+3.21.3
+======
+* Don't create invalid UTF-8 window description strings [Rui; #765535]
+* Convert window titles and wm_class to UTF-8 [Rui; #752788]
+* Communicate tiled state to GTK+ on wayland [Olivier; #766860]
+* Use kill() to force-quit unresponsive wayland clients [Olivier; #767464]
+* Fix window position when unmaximizing via DND on wayland [Olivier; #764180]
+* Avoid full window redraws when using extended frame sync [Florian; #767798]
+
+Contributors:
+  Olivier Fourdan, Rui Matos, Florian Müllner
+
+Translations:
+  Cédric Valmary [oc]
+
 3.21.2
 ======
 * Clean up surface <-> shell interaction [Jonas; #763431]
diff --git a/configure.ac b/configure.ac
index 060e5e1..3d83443 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2,7 +2,7 @@ AC_PREREQ(2.62)
 
 m4_define([mutter_major_version], [3])
 m4_define([mutter_minor_version], [21])
-m4_define([mutter_micro_version], [2])
+m4_define([mutter_micro_version], [3])
 
 m4_define([mutter_version],
           [mutter_major_version.mutter_minor_version.mutter_micro_version])