chore(obstacle_cruise_planner): safe_distance_margin to 6.0m (autowarefoundation#949)

Author: shmpwk

autoware_launch/config/planning/scenario_planning/lane_driving/motion_planning/obstacle_cruise_planner/obstacle_cruise_planner.param.yaml

@@ -12,7 +12,7 @@
       idling_time: 2.0 # idling time to detect front vehicle starting deceleration [s]
       min_ego_accel_for_rss: -1.0 # ego's acceleration to calculate RSS distance [m/ss]
       min_object_accel_for_rss: -1.0 # front obstacle's acceleration to calculate RSS distance [m/ss]
-      safe_distance_margin : 6.0 # This is also used as a stop margin [m]
+      safe_distance_margin : 5.0 # This is also used as a stop margin [m]
       terminal_safe_distance_margin : 3.0 # Stop margin at the goal. This value cannot exceed safe distance margin. [m]
       hold_stop_velocity_threshold: 0.01 # The maximum ego velocity to hold stopping [m/s]
       hold_stop_distance_threshold: 0.3 # The ego keeps stopping if the distance to stop changes within the threshold [m]