Fix link to cron service

docs/installation-and-operations/configuration/incoming-emails/README.md

@@ -26,7 +26,7 @@ openproject run bundle exec rake redmine:email:receive_imap host='imap.gmail.com
 
 **Docker installation**
 
-The docker installation has a ["cron-like" daemon](https://github.com/opf/openproject/blob/dev/docker/cron) that will imitate the above cron job. You need to specify the following ENV variables (e.g., to your env list file)
+The docker installation has a ["cron-like" daemon](https://github.com/opf/openproject/blob/dev/docker/prod/cron) that will imitate the above cron job. You need to specify the following ENV variables (e.g., to your env list file)
 
 - `IMAP_SSL` set to true or false depending on whether the ActionMailer IMAP connection requires implicit TLS/SSL
 - `IMAP_PORT` `IMAP_HOST` set to the IMAP host and port of your connection