Update flake8-isort to 2.3

[pyup-bot]

There's a new version of flake8-isort available.
You are currently using 2.2.2. I have updated it to 2.3

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

Changelog

2.3

---

• Fix typo.
  [paltman]

• Add tox.ini and .editorconfig to config search.
  [cas--]

• Make this plugin compatible with flake8 hook.
  As the hook copies the files out of tree,
  flake8-isort never finds the correct configuration.
  [jaysonsantos]

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

Happy merging! 🤖

[coveralls]

Coverage remained the same at 100.0% when pulling 3f4884e on pyup-update-flake8-isort-2.2.2-to-2.3 into b61ef07 on master.