fix: update postgres volume mount path for PostgreSQL 18+ compatibility

Co-authored-by: Kaniska244 <[email protected]>

Author: Copilot

src/java-postgres/.devcontainer/docker-compose.yml

@@ -44,7 +44,7 @@ services:
       retries: 5
       start_period: 30s
     volumes:
-      - postgres-data:/var/lib/postgresql/data
+      - postgres-data:/var/lib/postgresql
     environment:
       # NOTE: POSTGRES_DB/USER/PASSWORD should match values in app container
       POSTGRES_PASSWORD: postgres