Update simplejson to 3.17.6

[pyup-bot]

This PR updates simplejson from 3.17.3 to 3.17.6.

Changelog

3.17.6

* Declare support for Python 3.10 and add wheels
https://github.com/simplejson/simplejson/pull/291
https://github.com/simplejson/simplejson/pull/292

3.17.5

* Fix the C extension module to harden is_namedtuple against looks-a-likes such
as Mocks. Also prevent dict encoding from causing an unraised SystemError when
encountering a non-Dict. Noticed by running user tests against a CPython
interpreter with C asserts enabled (COPTS += -UNDEBUG).
https://github.com/simplejson/simplejson/pull/284

3.17.4

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

Links

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