chore(deps): update roundcube/roundcubemail docker tag to v1.6.11

Author: renovate[bot]

build-images.sh

@@ -38,7 +38,7 @@ buildah add "${container}" ui/dist /ui
 # Select you image(s) with the label org.nethserver.images
 # ghcr.io/xxxxx is the GitHub container registry or your own registry or docker.io for Docker Hub
 # The image tag is set to latest by default, but can be overridden with the IMAGETAG environment variable
-# --label="org.nethserver.images=docker.io/mariadb:10.11.5 docker.io/roundcube/roundcubemail:1.6.4-apache"
+# --label="org.nethserver.images=docker.io/mariadb:10.11.5 docker.io/roundcube/roundcubemail:1.6.11-apache"
 # rootfull=0 === rootless container
 # tcp-ports-demand=1 number of tcp Port to reserve , 1 is the minimum, can be udp or tcp
 buildah config --entrypoint=/ \