FIX: Use example domain in mail receiver example config
FIX: Use example domain in mail receiver example config

Context at https://meta.discourse.org/t/-/193664/4?u=falco

Co-authored-by: Jay Pfaffman <8bfd13cad0bc4b2ac41d9e235951e72c9b62c2aa@literatecomputing.com>

discourse/discourse_docker,discourse/discourse_docker,discourse/discourse_docker