Create Server

Hi I see this issue when i using SDK 
in lkdevelopment/hetzner-cloud-php-sdk/src/Models/Servers/Servers.php
line 240 
        if (! empty($firewalls)) {
            $parameters['firewalls'] = json_encode($firewalls);
        }

must remove json_encode see https://docs.hetzner.cloud/#servers-create-a-server 
thanks also will be good if you add anther options  
