python3Packages.pygobject-stubs: fix build

pkgs/development/python-modules/pygobject-stubs/default.nix

@@ -3,6 +3,7 @@
   buildPythonPackage,
   fetchFromGitHub,
   setuptools,
+  typing-extensions,
 }:
 
 buildPythonPackage rec {
@@ -19,6 +20,8 @@ buildPythonPackage rec {
 
   build-system = [ setuptools ];
 
+  dependencies = [ typing-extensions ];
+
   # This package does not include any tests.
   doCheck = false;