Fix faulty filename as per systemd unit file reference.

[config] / bullseye / other_files / prune.sh

#!/bin/sh
set -e
set -x
service microblogpub stop
microblogdir=/home/plom/testing.microblog.pub
cd "${microblogdir}"
cp -r data/microblogpub.db data/microblogpub.db.bak.$(date +%a)
su -lc "cd ${microblogdir} && poetry run inv prune-old-data" - plom
service microblogpub start
echo "last microblog pruning at $(date)" >> /home/plom/prune_log.txt