Merge #1004

1004: update roundcube r=kaiyou a=hoellen

## What type of PR?

enhancement (update)

## What does this PR do?
Updates roundcube to 1.3.9

### Related issue(s)
none

## Prerequistes
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.

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


Co-authored-by: hoellen <dev@hoellen.eu>

webmails/roundcube/Dockerfile

@@ -5,7 +5,7 @@ RUN apt-get update && apt-get install -y \
   && rm -rf /var/lib/apt/lists \
   && echo "ServerSignature Off" >> /etc/apache2/apache2.conf
 
-ENV ROUNDCUBE_URL https://github.com/roundcube/roundcubemail/releases/download/1.3.8/roundcubemail-1.3.8-complete.tar.gz
+ENV ROUNDCUBE_URL https://github.com/roundcube/roundcubemail/releases/download/1.3.9/roundcubemail-1.3.9-complete.tar.gz
 
 RUN apt-get update && apt-get install -y \
       zlib1g-dev python3-jinja2 \