Allow spin to be installed via Homebrew

[jaydrogers]

👉 Describe the problem

• Some Mac users may want to use spin to simply install and manage spin

🏆 How to solve this problem

• Submit spin to be installed via Homebrew
• See if spin is even available and doesn't collide with other projects

💯 How do we validate the problem is solved?

• Users will be able to do brew install spin to easily install Spin to their machine

[wblondel]

FYI the formula spin already exists, but it is for another piece of software

[jaydrogers]

I saw that. There's a good chance we just keep it with the installer from our website for now. Thanks for the heads up!