[gnome-nibbles] flatpak: build with meson instead of autotools

[Jordan Petridis <jpetridis src gnome org>]

commit a7d4ac75fe6dace356577aa6d2e8f33358fcd943
Author: Jordan Petridis <jpetridis gnome org>
Date:   Tue Jul 2 20:29:57 2019 +0300

    flatpak: build with meson instead of autotools

 org.gnome.Nibbles.json | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/org.gnome.Nibbles.json b/org.gnome.Nibbles.json
index ea7498c..be08e8b 100644
--- a/org.gnome.Nibbles.json
+++ b/org.gnome.Nibbles.json
@@ -30,6 +30,8 @@
         "org.gnome.games-support.modules.json",
         {
             "name": "gnome-nibbles",
+            "buildsystem": "meson",
+            "builddir" : true,
             "sources": [
                 {
                     "type": "git",