shorten composer/module table on usage overview

Author: gregor-j

usage.md

@@ -5,10 +5,10 @@ Use `composer require` to add PHP/SAP to your project. Depending on the
  package.
 
  Module Author  | Module      | supported PHP versions | composer require
- -------------- | ----------- | ---------------------- | -------------------------
- Eduard Koucky  | `saprfc`    | PHP 4.x - 5.5.x        | `composer require php-sap/saprfc-koucky`
- Piers Harding  | `sapnwrfc`  | PHP 5.x                | `composer require php-sap/saprfc-harding`
- Gregor Kralik  | `sapnwrfc`  | PHP 7.x                | `composer require php-sap/saprfc-kralik`
+ -------------- | ----------- | ---------------------- | ------------------------
+ Eduard Koucky  | `saprfc`    | PHP 4.x - 5.5.x        | `php-sap/saprfc-koucky`
+ Piers Harding  | `sapnwrfc`  | PHP 5.x                | `php-sap/saprfc-harding`
+ Gregor Kralik  | `sapnwrfc`  | PHP 7.x                | `php-sap/saprfc-kralik`
 
 The namespace of the library is `\phpsap\saprfc`, no matter which library you use.