joystick_relay.py likely not runnable on Noetic

[sloretz]

@bmagyar FYI I noticed this while checking ros/rosdistro#25265

It looks like joystick_relay.py will get installed with the wrong shebang on Noetic, and so it won't be runnable. See this ROS wiki page for more info: http://wiki.ros.org/UsingPython3/SourceCodeChanges#Changing_shebangs

To fix, the shebang should be changed to #!/usr/bin/env python

twist_mux/scripts/joystick_relay.py

Line 1 in a2818fd

#! /usr/bin/python

and the script should be installed with catkin_install_python()

twist_mux/CMakeLists.txt

Lines 40 to 41 in a2818fd

	install(PROGRAMS scripts/joystick_relay.py
	DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION})