ladybird: add updateScript (#354027)

pkgs/applications/networking/browsers/ladybird/default.nix

@@ -26,6 +26,7 @@
 , Cocoa
 , Foundation
 , OpenGL
+, unstableGitUpdater
 }:
 
 let
@@ -148,6 +149,8 @@ stdenv.mkDerivation (finalAttrs: {
     nixosTest = nixosTests.ladybird;
   };
 
+  passthru.updateScript = unstableGitUpdater { };
+
   meta = with lib; {
     description = "Browser using the SerenityOS LibWeb engine with a Qt or Cocoa GUI";
     homepage = "https://ladybird.org";