add note to compose file

Signed-off-by: Felix Bartels <felix@host-consultants.de>

docker-compose.mail.yml

@@ -4,7 +4,7 @@ services:
   mail:
     image: tvial/docker-mailserver:release-v6.2.0
     restart: unless-stopped
-    hostname: mail
+    hostname: mail # hostname and domainname may need to be commented on some platforms (e.g. ChromeOS)
     domainname: ${LDAP_DOMAIN}
     container_name: ${COMPOSE_PROJECT_NAME}_mail
     ports:

docker-compose.yml

@@ -257,7 +257,7 @@ services:
     image: ${docker_repo:-zokradonh}/kopano_core:${CORE_VERSION:-latest}
     read_only: true
     restart: unless-stopped
-    hostname: spooler
+    hostname: spooler # hostname and domainname may need to be commented on some platforms (e.g. ChromeOS)
     domainname: ${LDAP_DOMAIN}
     depends_on:
       - kopano_server