Update babel to 2.8.1

[pyup-bot]

This PR updates Babel from 2.7.0 to 2.8.1.

Changelog

2.8.1

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This is solely a patch release to make running tests on Py.test 6+ possible.

Bugfixes
~~~~~~~~

* Support Py.test 6 - Aarni Koskela (747, 750, 752)

2.8.0

-------------

Improvements
~~~~~~~~~~~~

* CLDR: Upgrade to CLDR 36.0 - Aarni Koskela (679)
* Messages: Don't even open files with the "ignore" extraction method - sebleblanc (678)

Bugfixes
~~~~~~~~

* Numbers: Fix formatting very small decimals when quantization is disabled - Lev Lybin, miluChen (662)
* Messages: Attempt to sort all messages – Mario Frasca (651, 606)

Docs
~~~~

* Add years to changelog - Romuald Brunet
* Note that installation requires pytz - Steve (Gadget) Barnes

Links

• PyPI: https://pypi.org/project/babel
• Changelog: https://pyup.io/changelogs/babel/
• Homepage: http://babel.pocoo.org/
• Docs: https://pythonhosted.org/Babel/

[pyup-bot]

Closing this in favor of #218