[caribou] bump release to 0.4.21

[Parag Nemade <panemade src gnome org>]

commit ec15fe124c9da90af87390628c9f49deb2a682ef
Author: Parag Nemade <pnemade redhat com>
Date:   Tue Jul 19 11:05:06 2016 +0530

    bump release to 0.4.21

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index da9d976..3959dca 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,6 +1,6 @@
 AC_PREREQ([2.63])
 AC_INIT([caribou],
-        [0.4.20],
+        [0.4.21],
         [https://bugzilla.gnome.org/enter_bug.cgi?product=caribou],
         [caribou])