update roundcube to 1.5.2 (security fix)

New roundcube release (1.5.2) where a XSS is addressed: https://roundcube.net/news/2021/12/30/update-1.5.2-released

webmails/roundcube/Dockerfile

@@ -39,7 +39,7 @@ RUN set -eu \
  && apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false \
  && rm -rf /var/lib/apt/lists
 
-ENV ROUNDCUBE_URL https://github.com/roundcube/roundcubemail/releases/download/1.5.1/roundcubemail-1.5.1-complete.tar.gz
+ENV ROUNDCUBE_URL https://github.com/roundcube/roundcubemail/releases/download/1.5.2/roundcubemail-1.5.2-complete.tar.gz
 ENV CARDDAV_URL https://github.com/mstilkerich/rcmcarddav/releases/download/v4.3.0/carddav-v4.3.0.tar.gz
 
 RUN set -eu \