logger : log ping topic

src/modules/logger/logger.cpp

@@ -605,6 +605,7 @@ void Logger::add_default_topics()
 	add_topic("mission");
 	add_topic("mission_result");
 	add_topic("optical_flow", 50);
+	add_topic("ping");
 	add_topic("position_setpoint_triplet", 200);
 	add_topic("rate_ctrl_status", 30);
 	add_topic("safety");