Bump pillow from 8.3.2 to 8.4.0

Bumps [pillow](https://github.com/python-pillow/Pillow) from 8.3.2 to 8.4.0.
- [Release notes](https://github.com/python-pillow/Pillow/releases)
- [Changelog](https://github.com/python-pillow/Pillow/blob/main/CHANGES.rst)
- [Commits](python-pillow/Pillow@8.3.2...8.4.0)

---
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

@@ -28,7 +28,7 @@ multidict==5.1.0
 mystbin.py==2.1.3
 orjson==3.6.3
 parsedatetime==2.6
-Pillow==8.3.2
+Pillow==8.4.0
 psutil==5.8.0
 pycparser==2.20
 pygit2==1.7.0