Apply php-cs-fixer fix --rules nullable_type_declaration_for_default_null_value

Author: nicolas-grekas

MessageBirdTransport.php

@@ -31,7 +31,7 @@ final class MessageBirdTransport extends AbstractTransport
     private $token;
     private $from;
 
-    public function __construct(string $token, string $from, HttpClientInterface $client = null, EventDispatcherInterface $dispatcher = null)
+    public function __construct(string $token, string $from, ?HttpClientInterface $client = null, ?EventDispatcherInterface $dispatcher = null)
     {
         $this->token = $token;
         $this->from = $from;

Tests/MessageBirdTransportTest.php

@@ -25,7 +25,7 @@ final class MessageBirdTransportTest extends TransportTestCase
     /**
      * @return MessageBirdTransport
      */
-    public static function createTransport(HttpClientInterface $client = null): TransportInterface
+    public static function createTransport(?HttpClientInterface $client = null): TransportInterface
     {
         return new MessageBirdTransport('token', 'from', $client ?? new MockHttpClient());
     }