[gnome-games] flatpak: Pin down retro-gtk commit

[Alexander Mikhaylenko <alexm src gnome org>]

commit c53953108987ae536344a74f0e9e54c2648e19c5
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Mon Dec 28 10:55:14 2020 +0500

    flatpak: Pin down retro-gtk commit

 flatpak/org.gnome.Games.json | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/flatpak/org.gnome.Games.json b/flatpak/org.gnome.Games.json
index 40b2a5e1..c1146057 100644
--- a/flatpak/org.gnome.Games.json
+++ b/flatpak/org.gnome.Games.json
@@ -194,7 +194,8 @@
             "sources" : [
                 {
                     "type" : "git",
-                    "url" : "https://gitlab.gnome.org/GNOME/retro-gtk.git";
+                    "url" : "https://gitlab.gnome.org/GNOME/retro-gtk.git";,
+                    "commit" : "86c8e9a87fefc98b54390227984ed13b97bbe232"
                 }
             ]
         },