Bump pillow from 5.3.0 to 8.1.1

Bumps [pillow](https://github.com/python-pillow/Pillow) from 5.3.0 to 8.1.1.
- [Release notes](https://github.com/python-pillow/Pillow/releases)
- [Changelog](https://github.com/python-pillow/Pillow/blob/master/CHANGES.rst)
- [Commits](python-pillow/Pillow@5.3.0...8.1.1)

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

Author: dependabot[bot]

requirements.txt

@@ -18,7 +18,7 @@ numpy==1.19.5
 pandas==1.2.0
 parso==0.8.2
 pickleshare==0.7.5
-Pillow==8.1.0
+Pillow==8.1.1
 prompt-toolkit==3.0.18
 Pygments==2.9.0
 pyparsing==2.4.7