[retro-gtk] meson: Bump glib to 2.68

[Adrien Plazas <aplazas src gnome org>]

commit ebdab186c411d1401cc2f26f11494116364f0396
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Thu Apr 8 23:20:52 2021 +0200

    meson: Bump glib to 2.68
    
    This is needed to access g_memdup2() which replaces the now deprecated
    g_memdup().

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index a91503e..5c8dc92 100644
--- a/meson.build
+++ b/meson.build
@@ -19,7 +19,7 @@ retro_gtk_version = meson.project_version()
 retro_gtk_api_version = '1'
 retro_gtk_module = 'retro-gtk-' + retro_gtk_api_version
 
-glib_version = '>= 2.50'
+glib_version = '>= 2.68'
 gtk_version = '>= 3.22'
 
 epoxy = dependency ('epoxy')