application-title-bar: add passthru.updateScript

pkgs/by-name/ap/application-title-bar/package.nix

@@ -2,6 +2,7 @@
 , stdenv
 , fetchFromGitHub
 , kdePackages
+, nix-update-script
 }:
 
 stdenv.mkDerivation (finalAttrs: {
@@ -26,6 +27,8 @@ stdenv.mkDerivation (finalAttrs: {
     runHook postInstall
   '';
 
+  passthru.updateScript = nix-update-script { };
+
   meta = {
     description = "KDE Plasma6 widget with window controls";
     homepage = "https://github.com/antroids/application-title-bar";