updates readme to download latest version

Cyril Mizzi · Cyril Mizzi · commit c2e698f904da · 2017-08-07T17:10:38.000+02:00
diff --git a/README.md b/README.md
@@ -28,7 +28,7 @@ provider will be added.
 Simply run
 
 ```bash
-composer require 'studio-net/laravel-graphql:0.2-beta'
+composer require 'studio-net/laravel-graphql:dev-master'
 ```
 
 ... and add service provider to `config/app.php` :
