Installing Kyon147/laravel-shopify package

I added auth.php to the config folder to git rid of initial errors, but then I came to this error.

If I install as a plugin dependency I see this after adding the middleware:

<?php namespace Baberuth22\Shopify;

use System\Classes\PluginBase;
use Osiset\ShopifyApp\Http\Middleware\VerifyShopify;
use Cms\Classes\CmsController;
/**
 * Plugin class
 */
class Plugin extends PluginBase
{
    /**
     * register method, called when the plugin is first registered.
     */
    public function register()
    {

    }

    /**
     * boot method, called right before the request route.
     */
    public function boot()
    {
        // register the shopify middleware
        // $this->app['router']->aliasMiddleware('verify.shopify', VerifyShopify::class);
        CmsController::extend(function($controller) {
            $controller->middleware(VerifyShopify::class);
        });
    }