[gnome-sdk-images] Try switching back to GTK+ 3.22

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 46b2a88855a58dbf75937e5c3d48ef11368c466f
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Thu Sep 20 19:39:23 2018 -0500

    Try switching back to GTK+ 3.22
    
    Speculative workaround for this bug:
    
    https://gitlab.gnome.org/GNOME/gtk/issues/1349

 org.gnome.Sdk.json.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/org.gnome.Sdk.json.in b/org.gnome.Sdk.json.in
index bed32e1..da10f36 100644
--- a/org.gnome.Sdk.json.in
+++ b/org.gnome.Sdk.json.in
@@ -430,7 +430,7 @@
                 {
                     "type": "git",
                     "url": "https://gitlab.gnome.org/GNOME/gtk.git";,
-                    "branch": "gtk-3-24"
+                    "branch": "gtk-3-22"
                 }
             ]
         },