Bump pillow from 8.1.1 to 9.3.0

Bumps [pillow](https://github.com/python-pillow/Pillow) from 8.1.1 to 9.3.0.
- [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/8.1.1...9.3.0)

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

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

requirements.txt

@@ -6,7 +6,7 @@ matplotlib==3.1.1
 Flask==1.1.1
 Cython==0.29.13
 pyOpenSSL==19.0.0
-Pillow==8.1.1
+Pillow==9.3.0
 brotli==1.0.7
 cryptography==3.3.2
 protobuf==3.10.0