[libpanel] build: drop gtk version for CI

[Christian Hergert <chergert src gnome org>]

commit 356f204d9138f2abc86dd3eef715b79f59b01fcb
Author: Christian Hergert <chergert redhat com>
Date:   Tue Sep 6 16:48:41 2022 -0700

    build: drop gtk version for CI

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 568fcfa..cae140e 100644
--- a/meson.build
+++ b/meson.build
@@ -27,7 +27,7 @@ vapidir = join_paths(datadir, 'vala', 'vapi')
 
 # Check dependencies
 glib_req_version = '2.72'
-gtk_req_version = '4.7'
+gtk_req_version = '4.6'
 adwaita_req_version = '1.0'
 
 glib_req = '>= @0@'.format(glib_req_version)