Bump pillow from 7.1.0 to 8.1.1

Bumps [pillow](https://github.com/python-pillow/Pillow) from 7.1.0 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@7.1.0...8.1.1)

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

Author: dependabot[bot]

requirements.txt

@@ -61,7 +61,7 @@ parso==0.5.1
 partd==1.0.0
 pefile==2019.4.18
 pickleshare==0.7.5
-Pillow==7.1.0
+Pillow==8.1.1
 pkginfo==1.4.2
 prometheus-client==0.7.1
 prompt-toolkit==2.0.9