Bump pillow from 8.0.1 to 8.1.2

Bumps [pillow](https://github.com/python-pillow/Pillow) from 8.0.1 to 8.1.2.
- [Release notes](https://github.com/python-pillow/Pillow/releases)
- [Changelog](https://github.com/python-pillow/Pillow/blob/master/CHANGES.rst)
- [Commits](python-pillow/Pillow@8.0.1...8.1.2)

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

Author: dependabot-preview[bot]

requirements.txt

@@ -9,6 +9,6 @@ Flask==1.1.2
 Werkzeug==1.0.1
 tqdm==4.54.1
 olefile==0.46
-Pillow==8.0.1
+Pillow==8.1.2
 py-bcrypt==0.4
 scikit_learn==0.22.2.post1