Bump pillow from 9.0.1 to 9.1.0

Bumps [pillow](https://github.com/python-pillow/Pillow) from 9.0.1 to 9.1.0.
- [Release notes](https://github.com/python-pillow/Pillow/releases)
- [Changelog](https://github.com/python-pillow/Pillow/blob/main/CHANGES.rst)
- [Commits](https://github.com/python-pillow/Pillow/compare/9.0.1...9.1.0)

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

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

Pipfile

@@ -22,7 +22,7 @@ gunicorn = "*"
 imap-tools = "*"
 langdetect = "*"
 pathvalidate = "*"
-pillow = "~=9.0"
+pillow = "~=9.1"
 # Any version update to pikepdf requires a base image update
 pikepdf = "~=5.1"
 python-gnupg = "*"