Fix test_typeddict_errors test case on Python 3.11 (#28)

Integers are now accepted as types in many runtime contexts:
python/cpython#90802

Fixes #24.

Author: JukkaL

tests/testextensions.py

@@ -89,9 +89,9 @@ def test_typeddict_errors(self):
         with self.assertRaises(TypeError):
             issubclass(dict, Emp)  # type: ignore
         with self.assertRaises(TypeError):
-            TypedDict('Hi', x=1)
+            TypedDict('Hi', x=())
         with self.assertRaises(TypeError):
-            TypedDict('Hi', [('x', int), ('y', 1)])
+            TypedDict('Hi', [('x', int), ('y', ())])
         with self.assertRaises(TypeError):
             TypedDict('Hi', [('x', int)], y=int)