fixing StyleCI issues

Author: pavoltanuska

src/OneSignalChannel.php

@@ -29,7 +29,7 @@ public function __construct(OneSignalClient $oneSignal)
     public function send($notifiable, Notification $notification)
     {
         if (! $userIds = $notifiable->routeNotificationFor('OneSignal')) {
-            return null;
+            return;
         }
 
         $payload = $notification->toOneSignal($notifiable)->toArray();

tests/ChannelTest.php

@@ -6,9 +6,9 @@
 use GuzzleHttp\Psr7\Response;
 use Orchestra\Testbench\TestCase;
 use Berkayk\OneSignal\OneSignalClient;
+use Psr\Http\Message\ResponseInterface;
 use NotificationChannels\OneSignal\OneSignalChannel;
 use NotificationChannels\OneSignal\Exceptions\CouldNotSendNotification;
-use Psr\Http\Message\ResponseInterface;
 
 class ChannelTest extends TestCase
 {