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

[Michael Catanzaro <mcatanzaro src gnome org>]

commit c0bee1ebe0d5a20a23950e092466e80a81313d95
Author: Michael Catanzaro <mcatanzaro posteo net>
Date:   Fri Sep 21 23:27:05 2018 +0000

    Revert "Try switching back to GTK+ 3.22"
    
    This reverts commit 46b2a88855a58dbf75937e5c3d48ef11368c466f

 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 b917a02..1d9277f 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-3-22"
+                    "branch": "gtk-3-24"
                 }
             ]
         },