[gnome-nibbles] Bump GTK+ to 3.18

[Iulian Radu <iulianradu src gnome org>]

commit 437402127282fb66c6cdcb7801ad93cff040e06e
Author: Iulian Radu <iulian radu67 gmail com>
Date:   Thu Feb 11 14:42:41 2016 +0200

    Bump GTK+ to 3.18

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 1cfd50c..8d0d8cb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -24,7 +24,7 @@ dnl Dependencies
 dnl ###########################################################################
 
 GLIB_REQUIRED=2.40.0
-GTK_REQUIRED=3.16.0
+GTK_REQUIRED=3.18.0
 RSVG_REQUIRED=2.32.0
 CANBERRA_GTK_REQUIRED=0.26
 CLUTTER_REQUIRED=1.22.0