emails/cli/setup/setups/02_api.php

<?php
use Psr\Container\ContainerInterface;

return [
    Psr\Http\Client\ClientInterface::class => function(ContainerInterface $container) {
        return new GuzzleHttp\Client([
            'base_uri' => $container->get('api_uri'),
            'headers' => [
                'Authorization' => "Bearer {$container->get('api_key')}"
            ]
        ]);
    }
];