[gnome-games] flatpak: Pin down mGBA commit

[Adrien Plazas <aplazas src gnome org>]

commit b595a01fbb4b251d964d81774a9b00929b596b72
Author: Exalm <exalm7659 gmail com>
Date:   Wed Apr 4 23:13:58 2018 +0500

    flatpak: Pin down mGBA commit
    
    This allows to avoid build issue until it's fixed
    upstream.

 flatpak/libretro-cores/libretro-mgba.json | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/flatpak/libretro-cores/libretro-mgba.json b/flatpak/libretro-cores/libretro-mgba.json
index 2be887d..b1734c5 100644
--- a/flatpak/libretro-cores/libretro-mgba.json
+++ b/flatpak/libretro-cores/libretro-mgba.json
@@ -17,7 +17,8 @@
             "sources": [
                 {
                     "type": "git",
-                    "url": "https://github.com/libretro/mgba";
+                    "url": "https://github.com/libretro/mgba";,
+                    "branch": "a5e1a1b47ebfaf045d559cd2a29f0a4b69f6f59c"
                 },
                 {
                     "type": "file",