position_setpoint_triplet topic: set the timestamp when publishing

src/modules/mavlink/mavlink_receiver.cpp

@@ -788,6 +788,7 @@ MavlinkReceiver::handle_message_set_position_target_local_ned(mavlink_message_t
 				} else {
 					/* It's not a pure force setpoint: publish to setpoint triplet  topic */
 					struct position_setpoint_triplet_s pos_sp_triplet = {};
+					pos_sp_triplet.timestamp = hrt_absolute_time();
 					pos_sp_triplet.previous.valid = false;
 					pos_sp_triplet.next.valid = false;
 					pos_sp_triplet.current.valid = true;