lua-language-server: add update script

pkgs/development/tools/language-servers/lua-language-server/default.nix

@@ -7,6 +7,7 @@
   CoreFoundation,
   Foundation,
   ditto,
+  nix-update-script,
 }:
 
 stdenv.mkDerivation (finalAttrs: {
@@ -84,6 +85,8 @@ stdenv.mkDerivation (finalAttrs: {
   # some tests require local networking
   __darwinAllowLocalNetworking = true;
 
+  passthru.updateScript = nix-update-script { };
+
   meta = with lib; {
     description = "A language server that offers Lua language support";
     homepage = "https://github.com/luals/lua-language-server";