chore(ops/besadii): switch from buildGo to buildGoModule

Change-Id: I0457419d6b74d4f4c3c999a656a22ddd6c9d9ac3
Reviewed-on: https://cl.snix.dev/c/snix/+/30186
Tested-by: besadii
Reviewed-by: Ryan Lahfa <masterancpp@gmail.com>
Reviewed-by: Florian Klink <flokli@flokli.de>

ops/besadii/default.nix

@@ -1,8 +1,20 @@
 # This program is used as a Gerrit hook to trigger builds on
 # Buildkite and perform other maintenance tasks.
-{ depot, ... }:
+{ pkgs, ... }@args:
 
-depot.nix.buildGo.program {
+let
+  inherit (pkgs) lib;
+in
+
+pkgs.buildGoModule {
   name = "besadii";
-  srcs = [ ./main.go ];
+  src = lib.fileset.toSource {
+    root = ./.;
+    fileset = lib.fileset.unions [
+      ./main.go
+      ./go.mod
+    ];
+  };
+  # No third party dependencies
+  vendorHash = null;
 }