Revert "const& in publish_pid_state"

This reverts commit ee356de.

include/control_toolbox/pid_ros.hpp

@@ -407,7 +407,7 @@ class PidROS
 
   void set_parameter_event_callback();
 
-  void publish_pid_state(double cmd, double error, const rclcpp::Duration & dt);
+  void publish_pid_state(double cmd, double error, rclcpp::Duration dt);
 
   void declare_param(const std::string & param_name, rclcpp::ParameterValue param_value);
 

src/pid_ros.cpp

@@ -269,7 +269,7 @@ void PidROS::set_gains(double p, double i, double d, double i_max, double i_min,
   }
 }
 
-void PidROS::publish_pid_state(double cmd, double error, const rclcpp::Duration & dt)
+void PidROS::publish_pid_state(double cmd, double error, rclcpp::Duration dt)
 {
   Pid::Gains gains = pid_.get_gains();