Update idna to 3.1

[pyup-bot]

This PR updates idna from 2.6 to 3.1.

Changelog

3.1

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

- Ensure license is included in package (Thanks, Julien Schueller)
- No longer mark wheel has universal (Thanks, Matthieu Darbois)
- Test on PowerPC using Travis CI

3.0

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

- Python 2 is no longer supported (the 2.x branch supports Python 2,
use "idna<3" in your requirements file if you need Python 2 support)
- Support for V2 UTS 46 test vectors.

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.

2.9

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

- Update to Unicode 12.1.0.
- Prohibit A-labels ending with a hyphen (Thanks, Julien Bernard!)
- Future-proofing: Test on Python 3.7 and 3.8, don't immediately
fail should Python 4 come along.
- Made BSD 3-clause license clearer

2.8

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

- Update to Unicode 11.0.0.
- Provide more specific exceptions for some malformed labels.

2.7

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

- Update to Unicode 10.0.0.
- No longer accepts dot-prefixed domains (e.g. ".example") as valid.
This is to be more conformant with the UTS 46 spec. Users should
strip dot prefixes from domains before processing.

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 #960