Merge #3439

3439: fix container name r=mergify[bot] a=Pegoku

## What type of PR?

documentation

## What does this PR do?
fixed the container name.

### Related issue(s)
none

## Prerequisites
Before we can consider review and merge, please make sure the following list is done and checked.
If an entry in not applicable, you can check it or remove it from the list.

- [ ] In case of feature or enhancement: documentation updated accordingly
- [ ] Unless it's docs or a minor change: add [changelog](https://mailu.io/master/contributors/workflow.html#changelog) entry file.


Co-authored-by: Pegoku <81113533+Pegoku@users.noreply.github.com>

docs/maintain.rst

@@ -46,8 +46,8 @@ In the case of *certbot* you could write a script to be executed as `deploy hook
   #!/bin/sh
   cp /etc/letsencrypt/live/domain.com/privkey.pem /mailu/certs/key.pem || exit 1
   cp /etc/letsencrypt/live/domain.com/fullchain.pem /mailu/certs/cert.pem || exit 1
-  docker exec mailu_front_1 nginx -s reload
-  docker exec mailu_front_1 doveadm reload
+  docker exec mailu-front-1 nginx -s reload
+  docker exec mailu-front-1 doveadm reload
 
 And the certbot command you will use in crontab would look something like: