Laravel 5.11 Composer Update Error

The oriceon-oauth-5-laravel package was installed by my friend and I pulled the code from git. I run the command composer update, but it throws the following error

exception 'Symfony\Component\Debug\Exception\FatalErrorException' with message 'Class 'Artdarek\OAuth\OAuthServiceProvider' not found' in /var/www/html/test/vendor/laravel/framework/src/Illuminate/Foundation/ProviderRepository.php:146

I resolved this temporarily by commenting the service providers and aliases in app.php file.

So,what is the correct way to resolve this issue. Its happening after installing the packages in laravel 5.11

via Chebli Mohamed