Merge branch '4.4' into 5.2

* 4.4:
  [CS] Replace easy occurences of ?: with ??

Author: derrabus

Transport/AbstractTransport.php

@@ -35,7 +35,7 @@ abstract class AbstractTransport implements TransportInterface
     public function __construct(EventDispatcherInterface $dispatcher = null, LoggerInterface $logger = null)
     {
         $this->dispatcher = class_exists(Event::class) ? LegacyEventDispatcherProxy::decorate($dispatcher) : $dispatcher;
-        $this->logger = $logger ?: new NullLogger();
+        $this->logger = $logger ?? new NullLogger();
     }
 
     /**

Transport/Smtp/SmtpTransport.php

@@ -44,7 +44,7 @@ public function __construct(AbstractStream $stream = null, EventDispatcherInterf
     {
         parent::__construct($dispatcher, $logger);
 
-        $this->stream = $stream ?: new SocketStream();
+        $this->stream = $stream ?? new SocketStream();
     }
 
     public function getStream(): AbstractStream