Add Homebrew cask

[houmain]

Thank you very much for making this driver available! I am using it for the MacOS port of my project keymapper. So far it works very well.

Have you thought about adding a homebrew cask for this project, which could be made a shared dependency of Karabiner-Elements and other applications? I think this would prevent many issues with incompatible installations.

Thanks!

[boldandbrad]

I second this ask. As someone who has used keymapper and other clients that depend on this driver (kanata), I think it would be extremely useful to have an automated way to install via something like homebrew, like houmain is suggesting.

Main benefits:

• version compatibility
• easily scriptable installation and setup for users without having to install all of karabiner-elements if not otherwise used (think dotfiles/system configuration)

An alternative could be making it possible for client creators to bundle the driver with their clients/apps like karabiner elements does. But I expect there would be additional licensing and/or technical challenges with that approach.