root/pypi: links for ringing-lib

root/pypi ringing-lib-0.4.0.tar.gz
root/pypi ringing-lib-0.3.0.tar.gz
root/pypi ringing-lib-0.2.0.tar.gz
root/pypi ringing-lib-0.1.0.tar.gz
root/pypi ringing-lib-0.2.1_1.tar.gz