Bump pillow from 9.0.1 to 9.1.1

Bumps [pillow](https://github.com/python-pillow/Pillow) from 9.0.1 to 9.1.1.
- [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...9.1.1)

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

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

requirements.txt

@@ -13,7 +13,7 @@ bleach-allowlist==1.0.3
 gunicorn==20.1.0
 lxml==4.8.0
 Markdown==3.3.7
-Pillow==9.0.1
+Pillow==9.1.1
 psycopg2-binary==2.9.3
 python-dotenv==0.20.0
 requests==2.27.1