Change db volume mount path

[Kanakanajm]

When following the setup instruction, an error occur after the docker compose up step:

Error response from daemon: failed to create task for container: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: error during container init: error mounting "/home/jackie/esid_volumes/postgres_data" to rootfs at "/var/lib/postgresql/data": change mount propagation through procfd: open o_path procfd: open /var/lib/docker/overlay2/470a780bbb3d6cd9e777588ff4d82b9338d72aa0b0f2410ecf57bd5bf0630a6a/merged/var/lib/postgresql/data: no such file or directory: unknown

Because docker is pulling the latest PostgreSQL which is PostgreSQL 18 at the time and PGDATA path was changed after the release as described in this issue.
I just fix PostgreSQL's version to 18 and update the PGDATA path in docker-compose.yml. Another possible fix would be downgrade PostgreSQL to <18.