Update flake8 to 3.5.0

[pyup-bot]

There's a new version of flake8 available.
You are currently using 3.4.1. I have updated it to 3.5.0

These links might come in handy: PyPI | Changelog | Repo

Changelog

3.5.0

---

You can view the 3.5.0 milestone_ on GitLab for more details.

New Dependency Information

• Allow for PyFlakes 1.6.0 (See also GitLab359_)

• Start using new PyCodestyle checks for bare excepts and ambiguous identifier
  (See also GitLab361_)

Features

• Print out information about configuring VCS hooks (See also GitLab335_)

• Allow users to develop plugins "local" to a repository without using
  setuptools. See our documentation on local plugins for more information.
  (See also GitLab357_)

Bugs Fixed

• Catch and helpfully report UnicodeDecodeError\ s when parsing
  configuration files. (See also GitLab358_)

.. all links
.. _3.5.0 milestone:
https://gitlab.com/pycqa/flake8/milestones/20

.. issue links
.. _GitLab335:
https://gitlab.com/pycqa/flake8/issues/335
.. _GitLab357:
https://gitlab.com/pycqa/flake8/issues/357
.. _GitLab358:
https://gitlab.com/pycqa/flake8/issues/358
.. _GitLab359:
https://gitlab.com/pycqa/flake8/issues/359
.. _GitLab361:
https://gitlab.com/pycqa/flake8/issues/361

.. merge request links

Got merge conflicts? Close this PR and delete the branch. I'll create a new PR for you.

Happy merging! 🤖

[pyup-bot]

Closing this in favor of #67