Remove old links from SMTP test server suggestions (#2085)
Remove old links from SMTP test server suggestions (#2085)

FakeSMTP's repo is read-only and hasn't been updated since 2016, so I removed it. The link to FakeEmail's repo was pointing at a fork that also hasn't been updated since 2016, so i changed the link to one that has more activity. Also smtp4dev has been moved to Github and works on Linux, so I updated its entry to reflect that.
PHPMailer/PHPMailer,jimjag/PHPMailer,nawawi/PHPMailer,nawawi/PHPMailer,PHPMailer/PHPMailer,jimjag/PHPMailer