notes: reword autocert/acme to acme/autocert
#### <sub><sup><a name="v551-note-4326" href="#v551-note-4326">:link:</a></sup></sub> fix
-* If you are using LetsEncrypt, you will want to upgrade to this version because it includes a fix for a [bug](https://github.com/concourse/concourse/issues/4326) where updating existing autocert/acme certificates fails #4395.
+* If you are using LetsEncrypt, you will want to upgrade to this version because it includes a fix for a [bug](https://github.com/concourse/concourse/issues/4326) where updating existing acme/autocert certificates fails #4395.
tldr: upsert autocert certs.
