Name the MariaDB data volume so backup restore is reused

docker-compose.yml

@@ -34,3 +34,5 @@ volumes:
     # Fixed name so the volume created earlier by `docker run -v cleo-pgdata:...` is reused.
     name: cleo-pgdata
   cleo-mariadb-data:
+    # Fixed name so the backup restore into the named volume is reused.
+    name: cleo-mariadb-data