python3Packages.pyrad: set updateScript (#444819)

pkgs/development/python-modules/pyrad/default.nix

@@ -2,6 +2,7 @@
   buildPythonPackage,
   fetchFromGitHub,
   lib,
+  nix-update-script,
   unittestCheckHook,
   poetry-core,
 }:
@@ -29,6 +30,10 @@ buildPythonPackage {
 
   pythonImportsCheck = [ "pyrad" ];
 
+  passthru.updateScript = nix-update-script {
+    extraArgs = [ "--version=branch" ];
+  };
+
   meta = {
     description = "Python RADIUS Implementation";
     homepage = "https://github.com/pyradius/pyrad";