[gnome-continuous] Build GTK 3.24

[Emmanuele Bassi <ebassi src gnome org>]

commit 8ac32c33aa39c9f1309aeacbeeb36040a048779e
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Thu Sep 6 11:31:03 2018 +0100

    Build GTK 3.24
    
    This is the last GTK 3.x stable series.

 manifest.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/manifest.json b/manifest.json
index c18a468..7f46def 100644
--- a/manifest.json
+++ b/manifest.json
@@ -659,7 +659,7 @@
 
                {"src": "gnome:gtk.git",
                 "name": "gtk3",
-                "branch": "gtk-3-22",
+                "branch": "gtk-3-24",
                 "config-opts": ["--enable-installed-tests",
                                  "--enable-wayland-backend",
                                  "--enable-x11-backend"],