Bump pillow from 5.4.1 to 9.0.0

Bumps [pillow](https://github.com/python-pillow/Pillow) from 5.4.1 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](https://github.com/python-pillow/Pillow/compare/5.4.1...9.0.0)

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

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

requirements.txt

@@ -6,7 +6,7 @@ pandas==0.23.4
 tensorflow==1.12.0
 Keras==2.2.4
 ipython==7.3.0
-Pillow==5.4.1
+Pillow==9.0.0
 python-dotenv==0.10.1
 PyYAML==3.13
 matplotlib>=3.1.0