gnomeExtensions.argos: set `passthru.updateScript`

pkgs/desktops/gnome/extensions/argos/default.nix

···
-{ fetchFromGitHub, lib, stdenv }:
+{ fetchFromGitHub, lib, stdenv, unstableGitUpdater }:
 
 stdenv.mkDerivation rec {
   pname = "argos";
···
   passthru = {
     extensionUuid = "[e-mail]";
     extensionPortalSlug = "argos";
+    updateScript = unstableGitUpdater { };
   };
 
   meta = with lib; {