Missing namespace from composer library

Hi everyone,
I'm new to CodeIgniter and I'm testing around with it right now. According to the docs, libraries from composer should be loaded automatically.
https://codeigniter4.github.io/CodeIgnit...oader.html
I've run this composer command to add a Steam login library.

Code:

composer require vikas5914/steam-auth:1.*

However, I'll get this error:

Code:

Class "App\Controllers\Vikas5914\SteamAuth" not found

The according line in my project is the object creation from SteamAuth:

Code:

$steam = new Vikas5914\SteamAuth($config);

Do I'll need  to register the namespaces from the package somewhere? The library itself is shown within the vendor folder.

Thanks!