Updates to Python library dependencies

This version makes some minor updates to our Python library dependencies to address #40. The data is not changed from the previous release.

Updated version that corrects data entry errors

This follow-up release corrects a number of data entry errors identified during camera-ready preparations and additional manual review after publication.

Initial release

This version closely matches the data that we used in our CoNLL-2020 paper, with some minor corrections for some data entry errors.