chore: upgrade db to pgautoupgrade/pgautoupgrade:18-alpine, move volume mount to /var/lib/postgresql (PG18 data-dir layout)

compose.postgresql.yml

@@ -14,13 +14,13 @@ services:
     secrets:
       - db_password
   db:
-    image: pgautoupgrade/pgautoupgrade:16-alpine
+    image: pgautoupgrade/pgautoupgrade:18-alpine
     environment:
       - POSTGRES_USER=codimd
       - POSTGRES_PASSWORD_FILE=/run/secrets/db_password
       - POSTGRES_DB=codimd
     volumes:
-      - "postgres:/var/lib/postgresql/data"
+      - "postgres:/var/lib/postgresql"
     secrets:
       - db_password
     networks: