[Webhook] Added Sendgrid's webhook support (added in 6.4)

Author: TimoBakx

webhook.rst

@@ -84,8 +84,14 @@ Mailer service  Parser service name
 =============== ==========================================
 Mailgun         ``mailer.webhook.request_parser.mailgun``
 Postmark        ``mailer.webhook.request_parser.postmark``
+Sendgrid        ``mailer.webhook.request_parser.sendgrid``
 =============== ==========================================
 
+.. versionadded:: 6.4
+
+    Webhook support for the Sendgrid service was introduced in Symfony 6.4
+
+
 Set up the webhook in the third-party mailer. For Mailgun, you can do this
 in the control panel. As URL, make sure to use the ``/webhook/mailer_mailgun``
 path behind the domain you're using.