Add Illuminate\Contracts\Mail\Factory contract to MailFake class (#31809)

Author: Hasnayeen

src/Illuminate/Support/Testing/Fakes/MailFake.php

@@ -2,13 +2,14 @@
 
 namespace Illuminate\Support\Testing\Fakes;
 
+use Illuminate\Contracts\Mail\Factory;
 use Illuminate\Contracts\Mail\Mailable;
 use Illuminate\Contracts\Mail\Mailer;
 use Illuminate\Contracts\Mail\MailQueue;
 use Illuminate\Contracts\Queue\ShouldQueue;
 use PHPUnit\Framework\Assert as PHPUnit;
 
-class MailFake implements Mailer, MailQueue
+class MailFake implements Factory, Mailer, MailQueue
 {
     /**
      * The mailer currently being used to send a message.