Bump pillow from 7.2.0 to 8.1.1

Bumps [pillow](https://github.com/python-pillow/Pillow) from 7.2.0 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](https://github.com/python-pillow/Pillow/compare/7.2.0...8.1.1)

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

requirements.txt

@@ -32,7 +32,7 @@ opencv-python==4.4.0.42
 opt-einsum==3.3.0
 pandas==1.1.1
 pathspec==0.8.0
-Pillow==7.2.0
+Pillow==8.1.1
 progressbar2==3.52.1
 protobuf==3.13.0
 pyasn1==0.4.8