ast-grep: add updateScript

pkgs/by-name/as/ast-grep/package.nix

@@ -6,6 +6,7 @@
   installShellFiles,
   buildPackages,
   versionCheckHook,
+  nix-update-script,
   enableLegacySg ? false,
 }:
 
@@ -72,6 +73,8 @@ rustPlatform.buildRustPackage rec {
   versionCheckProgramArg = [ "--version" ];
   doInstallCheck = true;
 
+  passthru.updateScript = nix-update-script { };
+
   meta = with lib; {
     mainProgram = "ast-grep";
     description = "Fast and polyglot tool for code searching, linting, rewriting at large scale";