ytmdesktop: add passthru.updateScript

pkgs/by-name/yt/ytmdesktop/package.nix

@@ -13,6 +13,8 @@
 
   electron,
   commandLineArgs ? "",
+
+  nix-update-script,
 }:
 
 let
@@ -137,6 +139,8 @@ stdenv.mkDerivation (finalAttrs: {
     })
   ];
 
+  passthru.updateScript = nix-update-script { };
+
   meta = {
     changelog = "https://github.com/ytmdesktop/ytmdesktop/tag/v${finalAttrs.version}";
     description = "Desktop App for YouTube Music";