Merge branch '4.4' into 5.4

* 4.4:
  Mailer: remove port 99 for requestbin.com

Author: javiereguiluz

mailer.rst

@@ -217,7 +217,6 @@ OhMySMTP             ohmysmtp+smtp://API_TOKEN@default                    n/a
 
         # .env
         MAILER_DSN=mailgun+https://KEY:DOMAIN@requestbin.com
-        MAILER_DSN=mailgun+https://KEY:DOMAIN@requestbin.com:99
 
     Note that the protocol is *always* HTTPs and cannot be changed.