BLD: Temporarily reintroduce typing_extensions for python 3.10

Bas van Beek · howjmay · commit 9eff3c6f6d07 · 2021-09-29T23:44:35.000+08:00
Remove once python/typing#865 has been fixed
diff --git a/test_requirements.txt b/test_requirements.txt
@@ -11,3 +11,6 @@ cffi
 # For testing types. Notes on the restrictions:
 # - Mypy relies on C API features not present in PyPy
 mypy==0.910; platform_python_implementation != "PyPy"
+
+# TODO: Remove once 3.10.0.2 has been released (xref python/typing#865)
+typing_extensions==3.10.0.0; python_version == '3.10'
