[gnome-control-center] Bump required GTK+ version

[Kalev Lember <klember src gnome org>]

commit 0947bd3615ab5b02c018c8de2aa53f4b27b1403b
Author: Kalev Lember <klember redhat com>
Date:   Tue Sep 20 12:25:52 2016 +0200

    Bump required GTK+ version
    
    https://bugzilla.gnome.org/show_bug.cgi?id=771696

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 4beac27..079777b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -86,7 +86,7 @@ dnl Check that we meet the  dependencies
 dnl ==============================================
 
 GLIB_REQUIRED_VERSION=2.44.0
-GTK_REQUIRED_VERSION=3.21.5
+GTK_REQUIRED_VERSION=3.22.0
 PA_REQUIRED_VERSION=2.0
 CANBERRA_REQUIRED_VERSION=0.13
 GDKPIXBUF_REQUIRED_VERSION=2.23.0