add header

Author: aquintan4

ra_cpp_api/vacuum_cleaner_cpp/include/vacuum_cleaner_cpp/WebGUI.hpp

@@ -5,6 +5,7 @@
 #include <boost/beast/websocket.hpp>
 #include <boost/asio/connect.hpp>
 #include <boost/asio/ip/tcp.hpp>
+#include <boost/asio/strand.hpp>
 #include <nlohmann/json.hpp>
 #include "rclcpp/rclcpp.hpp"
 #include "nav_msgs/msg/odometry.hpp"