Update maintainerr.subdomain.conf.sample

add note about previous port

Author: pagdot

maintainerr.subdomain.conf.sample

@@ -1,7 +1,7 @@
 ## Version 2024/10/27
 # make sure that your maintainerr container is named maintainerr
 # make sure that your dns has a cname set for maintainerr
-# maintainerr v2.0.0+ only
+# maintainerr v2.0.0+ only. for prior versions, set upstream_port to 80
 
 server {
     listen 443 ssl;