Bump pillow from 8.2.0 to 8.3.1 (#131)

Bump pillow from 8.2.0 to 8.3.1 (#131)

Bumps [pillow](https://github.com/python-pillow/Pillow) from 8.2.0 to 8.3.1.
- [Release notes](https://github.com/python-pillow/Pillow/releases)
- [Changelog](https://github.com/python-pillow/Pillow/blob/master/CHANGES.rst)
- [Commits](https://github.com/python-pillow/Pillow/compare/8.2.0...8.3.1)

---
updated-dependencies:
- dependency-name: pillow
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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