Fix barman user's home directory

Dockerfile

@@ -13,10 +13,12 @@ RUN curl -o /etc/apt/trusted.gpg.d/apt.postgresql.org.asc --fail https://www.pos
 # Create barman user
 ENV BARMAN_UID=999
 ENV BARMAN_GID=999
+ENV BARMAN_DATA_DIR=/var/lib/barman
 
 RUN groupadd --system -g ${BARMAN_GID} barman && \
     useradd --system \
         -u ${BARMAN_UID} -g ${BARMAN_GID} \
+        -d ${BARMAN_DATA_DIR} \
         --shell /bin/bash \
         barman
 
@@ -33,7 +35,6 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         && sed -i 's/\(.*pam_loginuid.so\)/#\1/' /etc/pam.d/cron
 
 ENV BARMAN_CONF_DIR=/etc/barman.d/
-ENV BARMAN_DATA_DIR=/var/lib/barman
 ENV BARMAN_CRON_SCHEDULE="* * * * *"
 
 VOLUME ${BARMAN_DATA_DIR}
@@ -42,4 +43,4 @@ VOLUME ${BARMAN_CONF_DIR}
 COPY entrypoint.sh /
 ENTRYPOINT ["tini", "--", "/entrypoint.sh"]
 CMD ["cron", "-L", "3", "-f"]
-WORKDIR ${BARMAN_DATA_DIR}
+WORKDIR ${BARMAN_DATA_DIR}