Class 'Aura\Autoload\Loader' not found in wp-relinquish.php 

Hello,

I installed the wp relinquish plugin in wordpress, and I have executed the 'composer install' command. Aura dependency has been successfully installed and it is located in the vendor folder.  When I try to activate the plugin I get the following error: 
Class 'Aura\Autoload\Loader' not found in wp-relinquish.php.

Thanks for your help.
