Bump pillow from 8.1.0 to 8.1.1

Bumps [pillow](https://github.com/python-pillow/Pillow) from 8.1.0 to 8.1.1.
- [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/8.1.0...8.1.1

)

Signed-off-by: dependabot[bot] <support@github.com>