"xacro: in-order processing became default in ROS Melodic. You can drop the option" error

edit

https://github.com/EuropeanRoverChall... Using the link I wrote all commands which is given in "Install on the host system" section.

When I try this command:

$ roslaunch ur3_sim simulation.launch

It gives error like this:

    ... logging to /home/ubuntu4/.ros/log/f2319ee2-b808-11ed-bb34-1be4f5885cab/roslaunch-ubuntu4-6223.log
Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

xacro: in-order processing became default in ROS Melodic. You can drop the option.
No such file or directory: /home/ubuntu4/catkin_ws3/src/universal_robot/ur_description/urdf/common.gazebo.xacro [Errno 2] No such file or directory: '/home/ubuntu4/catkin_ws3/src/universal_robot/ur_description/urdf/common.gazebo.xacro'
when processing file: /home/ubuntu4/catkin_ws3/src/UR3_sim/ur3_sim_description/urdf/ur3_sim.urdf.xacro
RLException: while processing /home/ubuntu4/catkin_ws3/src/UR3_sim/ur3_sim_gazebo/launch/ur3_sim.launch:
while processing /home/ubuntu4/catkin_ws3/src/UR3_sim/ur3_sim_description/launch/ur3_sim_upload.launch:
Invalid <param> tag: Cannot load command parameter [robot_description]: command [['/opt/ros/noetic/lib/xacro/xacro', '--inorder', '/home/ubuntu4/catkin_ws3/src/UR3_sim/ur3_sim_description/urdf/ur3_sim.urdf.xacro', 'transmission_hw_interface:=hardware_interface/PositionJointInterface']] returned with code [2]. 

Param xml is <param name="robot_description" command="$(find xacro)/xacro --inorder '$(find ur3_sim_description)/urdf/ur3_sim.urdf.xacro' transmission_hw_interface:=$(arg transmission_hw_interface)"/>
The traceback for the exception was written to the log file