Add Homebrew to install docs (#3838)
Add Homebrew to install docs (#3838)

* add Homebrew to install docs

* add missing install instructions

* add 'cask' to macOS uninstall

* address PR comments on Mac install

* move to cask reinstall for update

TravisEz13/PowerShell,daxian-dbw/PowerShell,JamesWTruher/PowerShell-1,TravisEz13/PowerShell,PaulHigin/PowerShell,PaulHigin/PowerShell,JamesWTruher/PowerShell-1,TravisEz13/PowerShell,JamesWTruher/PowerShell-1,PaulHigin/PowerShell,daxian-dbw/PowerShell,daxian-dbw/PowerShell,PaulHigin/PowerShell,TravisEz13/PowerShell,JamesWTruher/PowerShell-1,daxian-dbw/PowerShell