Update flake8-commas to 2.1.0

[pyup-bot]

This PR updates flake8-commas from 2.0.0 to 2.1.0.

Changelog

2.1.0

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

- Remove upper bound on flake8.
(`Issue 67 <https://github.com/PyCQA/flake8-commas/issues/67>`_)
- Note: this project is no longer maintained, and now black
or https://github.com/asottile/add-trailing-comma is recommended instead.
(`Issue 63 <https://github.com/PyCQA/flake8-commas/pull/63>`_)
(`Issue 69 <https://github.com/PyCQA/flake8-commas/pull/69>`_)

Links

• PyPI: https://pypi.org/project/flake8-commas
• Changelog: https://pyup.io/changelogs/flake8-commas/
• Repo: https://github.com/PyCQA/flake8-commas/