Install on macOS via Homebrew in README
Install on macOS via Homebrew in README

The application is now packaged for Homebrew:
<https://github.com/Homebrew/homebrew-core/pull/25173>

Give instructions to install it from Homebrew for macOS (it's much
easier).

Thanks to @stek29 for the formula ;-)

Genymobile/scrcpy,Genymobile/scrcpy,Genymobile/scrcpy