Release typing_extensions to PyPI

[gvanrossum]

@JukkaL and I were discussing steps towards rolling out Protocols. An important step is releasing the typing_extensions package to PyPI. @ilevkivskyi are you interested in taking on this task? It's not hard -- create a PyPI account, and use twine (pip install twine) to upload it.

[ilevkivskyi]

Yes, I first need to finish few remaining issues found in CR of #464 (hopefully before the end of this week). I already have an account on PyPI (I published typing_inspect). The account name is the same as my GitHub account name.

[geyang]

Looking forward to seeing this on PyPI!

[ilevkivskyi]

OK, the package is now on PyPI!