Bump pillow from 9.0.1 to 9.1.0

Bumps [pillow](https://github.com/python-pillow/Pillow) from 9.0.1 to 9.1.0.
- [Release notes](https://github.com/python-pillow/Pillow/releases)
- [Changelog](https://github.com/python-pillow/Pillow/blob/main/CHANGES.rst)
- [Commits](python-pillow/Pillow@9.0.1...9.1.0)

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

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

Author: dependabot[bot]

requirements_test.txt

@@ -5,7 +5,7 @@ scipy==1.8.0
 matplotlib==3.5.1
 scikit-learn>=0.22.2,<1.1.0
 six==1.16.0
-Pillow==9.0.1
+Pillow==9.1.0
 tqdm==4.63.1
 statsmodels==0.13.2
 pydub==0.25.1