docs: document dynamic SSL certificate discovery for ACME providers

Author: umputun

README.md

@@ -163,6 +163,8 @@ In case if rules set as a part of docker compose environment, destination with t
 
 SSL mode (by default none) can be set to `auto` (ACME/LE certificates), `static` (existing certificate) or `none`. If `auto` turned on SSL certificate will be issued automatically for all discovered server names. User can override it by setting `--ssl.fqdn` value(s). In `auto` and `static` SSL mode, Reproxy will automatically add the `X-Forwarded-Proto` and `X-Forwarded-Port` headers. These headers are useful for services behind the proxy to know the original protocol (http or https) and port number used by the client.
 
+When using ACME with discovery providers (docker, file, consul), SSL certificates are automatically obtained for newly discovered servers without requiring a reproxy restart.
+
 ### ACME Challenges
 
 Reproxy supports two types of ACME challenges for SSL certificate validation: