ready for release into noetic/focal

this package passes pre-release tests:

generate_prerelease_script.py   https://raw.githubusercontent.com/ros-infrastructure/ros_buildfarm_config/production/index.yaml   noetic default ubuntu focal amd64   --custom-repo     pr2_kinematics__custom-5:git:https://github.com/PR2/pr2_kinematics.git:kinetic-devel   --level 0   --output-dir ./