Bump pillow from 7.2.0 to 8.1.1 (#399)

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>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements.txt

@@ -49,7 +49,7 @@ pathvalidate==2.2.1
 pexpect==4.8.0
 photoscript==0.1.0
 pickleshare==0.7.5
-Pillow==7.2.0
+Pillow==8.1.1
 pkginfo==1.5.0.1
 pluggy==0.12.0
 prompt-toolkit==3.0.4