Update simplejson to 3.17.4

[pyup-bot]

This PR updates simplejson from 3.17.2 to 3.17.4.

Changelog

3.17.4

* Upgrade cibuildwheel
https://github.com/simplejson/simplejson/pull/287

3.17.3

* Replaced Travis-CI and AppVeyor with Github Actions,
adding wheels for Python 3.9.
https://github.com/simplejson/simplejson/pull/283

Links

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

[coveralls]

Coverage remained the same at 86.413% when pulling 66863aa on pyup-update-simplejson-3.17.2-to-3.17.4 into 2716a32 on master.

[pyup-bot]

Closing this in favor of #341