Update idna to 2.10

[pyup-bot]

This PR updates idna from 2.9 to 2.10.

Changelog

2.10

+++++++++++++++++

- Update to Unicode 13.0.0.
- Throws a more specific exception if "xn--" is provided as a label.
- This is expected to be the last version that supports Python 2.

Links

• PyPI: https://pypi.org/project/idna
• Changelog: https://pyup.io/changelogs/idna/
• Repo: https://github.com/kjd/idna

[pyup-bot]

Closing this in favor of #1418