Merge pull request tuyakhov#4 from mrbig00/patch-1

Bug tuyakhov#3: Set proper mail subject

src/channels/MailChannel.php

@@ -40,6 +40,7 @@ public function send(NotifiableInterface $recipient, NotificationInterface $noti
         $this->mailer->compose($message->view, $message->viewData)
             ->setFrom(isset($message->from) ? $message->from : $this->from)
             ->setTo($recipient->routeNotificationFor('mail'))
+            ->setSubject($message->subject)
             ->send();
     }
-}
+}