[gnome-nibbles/arnaudb/wip/gtk4] Try to fix CI.

[Arnaud B. <arnaudb src gnome org>]

commit 738b227ca5f51371bb358474ea998d100392653e
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Tue Jun 16 18:35:17 2020 +0200

    Try to fix CI.

 org.gnome.Nibbles.json | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/org.gnome.Nibbles.json b/org.gnome.Nibbles.json
index 124f894..bc4c152 100644
--- a/org.gnome.Nibbles.json
+++ b/org.gnome.Nibbles.json
@@ -53,7 +53,8 @@
             "sources": [
                 {
                     "type": "git",
-                    "url": "https://gitlab.gnome.org/GNOME/libgnome-games-support.git";
+                    "url": "https://gitlab.gnome.org/GNOME/libgnome-games-support.git";,
+                    "branch": "arnaudb/wip/gtk4"
                 }
             ]
         },