Remove instructions about Chocolatey on Windows
Remove instructions about Chocolatey on Windows

The `hub` package is out of date and repeated attempts to contact the
maintainer and take over the package have failed.

https://chocolatey.org/packages/hub
https://github.com/github/hub/issues/1288
https://github.com/twsouthwick/github-hub-chocolatey/issues/1

github/hub,github/hub,github/hub,github/hub