Bump pillow from 6.2.1 to 9.0.0

Bumps [pillow](https://github.com/python-pillow/Pillow) from 6.2.1 to 9.0.0.
- [Release notes](https://github.com/python-pillow/Pillow/releases)
- [Changelog](https://github.com/python-pillow/Pillow/blob/main/CHANGES.rst)
- [Commits](python-pillow/Pillow@6.2.1...9.0.0)

---
updated-dependencies:
- dependency-name: pillow
  dependency-type: direct:production
...

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

requirements.txt

@@ -7,7 +7,7 @@ django-pagedown==2.2.1
 django-markdown-deux
 django-registration==3.2
 psycopg2==2.8.4
-Pillow==6.2.1
+Pillow==9.0.0
 requests
 gunicorn[gevent]==20.1.0
 gevent==21.1.2