fix: override the vendorHash

* this is a terrible hack but unfortunately it's necessary because
  buildGoModule computes the vendorHash after installing all Go modules
* although overriding the vendorHash works just fine, there's still
  something wrong because the overlay is not applied properly, as per

    kluctl --version
    kluctl version v2.22.1

Resolves:
Related: NixOS/nixpkgs#86349
Signed-off-by: Daniel-Andrei Minca <[email protected]>

overlays/kluctl/default.nix

@@ -4,6 +4,7 @@
   kluctl = prev.kluctl.override {
     buildGoModule = previousArgs: let self = prev.buildGoModule (previousArgs // {
       version = "2.25.0";
+      vendorHash = "sha256-TckT39wQn4dclcYSfxootv1Lw5+iYxY6/wwdUc1+Z6s=";
       src = prev.fetchFromGitHub {
         owner = "kluctl";
         repo = "kluctl";