maintainers/scripts/update.nix: Do not store updateScripts

For update script parallelization, we have started calling builtins.toJSON
on updateScripts, which triggers evaluation of paths and therefore their copying
to Nix store. This breaks update scripts that assume that they exist in nixpkgs
like dwarf-fortress.

https://github.com/NixOS/nixpkgs/issues/61935

Let’s stringify the paths before JSONification to prevent the evaluation.

maintainers/scripts/update.nix

@@ -122,7 +122,7 @@ let
   packageData = package: {
     name = package.name;
     pname = (builtins.parseDrvName package.name).name;
-    updateScript = pkgs.lib.toList package.updateScript;
+    updateScript = map builtins.toString (pkgs.lib.toList package.updateScript);
   };
 
 in pkgs.stdenv.mkDerivation {