fix: use Postgres PGDATA subdirectory

proxcenter-compose.yml

@@ -99,6 +99,9 @@ services:
       - POSTGRES_PASSWORD=${POSTGRES_PASSWORD}
       - POSTGRES_DB=${POSTGRES_DB:-proxcenter}
       - POSTGRES_INITDB_ARGS=--encoding=UTF8 --locale=C
+      # Use a child directory under the NFS bind mount so Postgres does not
+      # need to chmod the NFS mount root during initdb.
+      - PGDATA=/var/lib/postgresql/data/pgdata
     volumes:
       - ${DockerData}/proxcenter/postgres_data:/var/lib/postgresql/data
     # Port is intentionally not published. Postgres is reachable only