[Typing-sig] typing_extensions 3.10.0.0 has been released

I just released typing_extensions 3.10.0.0 and typing 3.10.0.0 to PyPI. typing_extensions now supports the new type system features introduced in Python 3.10. Notable additions include TypeGuard, ParamSpec, Concatenate, and OrderedDict. The typing backport library now explicitly disallows installation on Python 3.5 and later. Thanks to all the people who contributed to this release: Dominic Davis-Foster, Dawid Kraczkowski, Ken Jin, James Morris, Daniel Ciborowski, Nils K, Antonio Valentino, Noel Evans, and Guido van Rossum. If something is wrong with the release, please open an issue at https://github.com/python/typing/issues.