[rygel] build: Bump GTK+ requirement to 3.22

[Jens Georg <jensgeorg src gnome org>]

commit 8062d0cc77d5bdfb11293472bcc127e7dccfb78a
Author: Jens Georg <mail jensge org>
Date:   Mon Oct 22 16:58:02 2018 +0200

    build: Bump GTK+ requirement to 3.22

 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/configure.ac b/configure.ac
index c7efd55d..fe712a94 100644
--- a/configure.ac
+++ b/configure.ac
@@ -46,7 +46,7 @@ GSTPBU_REQUIRED=1.0
 GIO_REQUIRED=2.26
 GEE_REQUIRED=0.8.0
 LIBSOUP_REQUIRED=2.44.0
-GTK_REQUIRED=3.0
+GTK_REQUIRED=3.22
 MEDIAART_REQUIRED=0.7.0
 
 dnl Additional requirements for media-export plugin