contribution: Homebrew paperspace CLI formula

[itsayellow]

To install and upgrade (or uninstall) the Paperspace CLI binary on macOS, I have made a Homebrew (mac package manager) tap and formula "paperspace-cli":
https://github.com/itsayellow/homebrew-paperspace

I would be happy to share with a wider community, so if you want to put this in your documentation, it would be much appreciated.

I tried to get the Homebrew organization to add the paperspace-cli formula to homebrew-core, but it was judged "not notable enough": Homebrew/homebrew-core#38536