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

[Arnaud B. <arnaudb src gnome org>]

commit 2a837300916ef02d101513c991fba71af7a4ea8c
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Wed Sep 9 17:21:11 2020 +0200

    Try to fix CI.

 build-aux/org.gnome.Mines.json | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/build-aux/org.gnome.Mines.json b/build-aux/org.gnome.Mines.json
index d557f0e..6594567 100644
--- a/build-aux/org.gnome.Mines.json
+++ b/build-aux/org.gnome.Mines.json
@@ -39,7 +39,8 @@
                     "buildsystem": "meson",
                     "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"
                     }]
                 }
             ]