Bump autopep8 from 2.1.0 to 2.3.1

Bumps [autopep8](https://github.com/hhatto/autopep8) from 2.1.0 to 2.3.1.
- [Release notes](https://github.com/hhatto/autopep8/releases)
- [Commits](hhatto/autopep8@v2.1.0...v2.3.1)

---
updated-dependencies:
- dependency-name: autopep8
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>