Add Laravel 6 support

Author: dmitry-ivanov

README.md

@@ -2,9 +2,9 @@
 
 [<img src="https://user-images.githubusercontent.com/1286821/43083932-4915853a-8ea0-11e8-8983-db9e0f04e772.png" alt="Become a Patron" width="160" />](https://patreon.com/dmitryivanov)
 
-[![StyleCI](https://styleci.io/repos/59570052/shield?branch=master&style=flat)](https://styleci.io/repos/59570052)
-[![Build Status](https://travis-ci.org/dmitry-ivanov/laravel-console-mutex.svg?branch=master)](https://travis-ci.org/dmitry-ivanov/laravel-console-mutex)
-[![Coverage Status](https://coveralls.io/repos/github/dmitry-ivanov/laravel-console-mutex/badge.svg?branch=master)](https://coveralls.io/github/dmitry-ivanov/laravel-console-mutex?branch=master)
+[![StyleCI](https://styleci.io/repos/59570052/shield?branch=6.x&style=flat)](https://styleci.io/repos/59570052)
+[![Build Status](https://travis-ci.org/dmitry-ivanov/laravel-console-mutex.svg?branch=6.x)](https://travis-ci.org/dmitry-ivanov/laravel-console-mutex)
+[![Coverage Status](https://coveralls.io/repos/github/dmitry-ivanov/laravel-console-mutex/badge.svg?branch=6.x)](https://coveralls.io/github/dmitry-ivanov/laravel-console-mutex?branch=6.x)
 
 [![Latest Stable Version](https://poser.pugx.org/illuminated/console-mutex/v/stable)](https://packagist.org/packages/illuminated/console-mutex)
 [![Latest Unstable Version](https://poser.pugx.org/illuminated/console-mutex/v/unstable)](https://packagist.org/packages/illuminated/console-mutex)
@@ -45,7 +45,7 @@ Mutex for Laravel console commands.
 1. Install the package via Composer:
 
     ```shell
-    composer require illuminated/console-mutex
+    composer require "illuminated/console-mutex:^6.0"
     ```
 
 2. Use `Illuminated\Console\WithoutOverlapping` trait: