Merge branch '6.4' into 7.0

* 6.4:
  [Mailer] Mention webhook support in Mailer bridge overview

Author: OskarStark

mailer.rst

@@ -99,21 +99,21 @@ Using a 3rd Party Transport
 Instead of using your own SMTP server or sendmail binary, you can send emails
 via a third-party provider:
 
-===================== ===============================================
-Service               Install with
-===================== ===============================================
+===================== =============================================== ===============
+Service               Install with                                    Webhook support
+===================== =============================================== ===============
 `Amazon SES`_         ``composer require symfony/amazon-mailer``
 `Brevo`_              ``composer require symfony/brevo-mailer``
 `Infobip`_            ``composer require symfony/infobip-mailer``
-`Mailgun`_            ``composer require symfony/mailgun-mailer``
+`Mailgun`_            ``composer require symfony/mailgun-mailer``     yes
 `Mailjet`_            ``composer require symfony/mailjet-mailer``
 `MailPace`_           ``composer require symfony/mail-pace-mailer``
 `MailerSend`_         ``composer require symfony/mailer-send-mailer``
 `Mandrill`_           ``composer require symfony/mailchimp-mailer``
-`Postmark`_           ``composer require symfony/postmark-mailer``
+`Postmark`_           ``composer require symfony/postmark-mailer``    yes
 `Scaleway`_           ``composer require symfony/scaleway-mailer``
 `SendGrid`_           ``composer require symfony/sendgrid-mailer``
-===================== ==============================================
+===================== =============================================== ===============
 
 .. note::