Simplify composer command line (#95)

Author: derrabus

README.md

@@ -14,7 +14,7 @@ This library provides a way of avoiding usage of constructors when instantiating
 The suggested installation method is via [composer](https://getcomposer.org/):
 
 ```sh
-php composer.phar require "doctrine/instantiator:~1.0.3"
+composer require doctrine/instantiator
 ```
 
 ## Usage