root/pypi: links for prefer

root/pypi prefer-0.2.1.tar.gz
root/pypi prefer-0.2.1-py3-none-any.whl
root/pypi prefer-0.2.0.tar.gz
root/pypi prefer-0.2.0-py3-none-any.whl
root/pypi prefer-0.1.0.tar.gz