message: Update change stream example
diff: @@ -57,8 +57,7 @@ void watch_until(const mongocxx::client& client,
  int main() {
  mongocxx::instance inst{};
  - mongocxx::uri uri{"mongodb://localhost:27017/?minPoolSize=3&maxPoolSize=3"};
  - mongocxx::pool pool{uri};
  + mongocxx::pool pool{mongocxx::uri{}};
  try {
  auto entry = pool.acquire();
  