improve usage example for Zope.

README-zope.md

@@ -11,5 +11,5 @@ password zope_password
 Now you can invoke the script like :
 
 ```text
-./letsencrypt.sh --cron --domain example.com --hook ./zope-hook.sh
+./letsencrypt.sh [command [argument]] [parameter [argument]] [parameter [argument]] --hook ./zope-hook.sh
 ```