Readme: fix composer install (#48)

Author: petrparolek

README.md

@@ -23,7 +23,7 @@ Website 🚀 <a href="https://contributte.org">contributte.org</a> | Contact 
 To install latest version of `contributte/console-extra` use [Composer](https://getcomposer.org).
 
 ```bash
-composer install contributte/console-extra
+composer require contributte/console-extra
 ```
 
 ## Documentation