update script for go dependancies

flake.nix

@@ -25,6 +25,7 @@
             inherit (gomod2nix.legacyPackages.${system}) buildGoApplication;
           };
           devShells.default = callPackage ./shell.nix {
+            inherit source;
             inherit (gomod2nix.legacyPackages.${system}) mkGoEnv gomod2nix;
           };
         })

shell.nix

@@ -1,4 +1,6 @@
-{ pkgs ? (
+{
+  source,
+  pkgs ? (
     let
       inherit (builtins) fetchTree fromJSON readFile;
       inherit ((fromJSON (readFile ./flake.lock)).nodes) nixpkgs gomod2nix;
@@ -8,17 +10,17 @@
           (import "${fetchTree gomod2nix.locked}/overlay.nix")
         ];
       }
-  )
-, mkGoEnv ? pkgs.mkGoEnv
-, gomod2nix ? pkgs.gomod2nix
-}:
-
-let
-  goEnv = mkGoEnv { pwd = ./.; };
+  ),
+  mkGoEnv ? pkgs.mkGoEnv,
+  gomod2nix ? pkgs.gomod2nix,
+}: let
+  update_gomod2nix = pkgs.writeShellScriptBin "update_gomod2nix" ''
+    ${gomod2nix}/bin/gomod2nix --dir ${source} --outdir ./
+  '';
 in
   pkgs.mkShell {
     packages = [
-    goEnv
       gomod2nix
+      update_gomod2nix
     ];
   }