Update valet.md

Update to brew PHP version, [email protected] no longer recommended - standard php package installs 7.3

Author: JustSteveKing

valet.md

@@ -66,7 +66,7 @@ Both Valet and Homestead are great choices for configuring your Laravel developm
 
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 - Install or update [Homebrew](http://brew.sh/) to the latest version using `brew update`.
-- Install PHP 7.2 using Homebrew via `brew install php@7.2`.
+- Install PHP 7.3 using Homebrew via `brew install php`.
 - Install [Composer](https://getcomposer.org).
 - Install Valet with Composer via `composer global require laravel/valet`. Make sure the `~/.composer/vendor/bin` directory is in your system's "PATH".
 - Run the `valet install` command. This will configure and install Valet and DnsMasq, and register Valet's daemon to launch when your system starts.