Bump pillow from 8.1.0 to 8.1.1

Bumps [pillow](https://github.com/python-pillow/Pillow) from 8.1.0 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](https://github.com/python-pillow/Pillow/compare/8.1.0...8.1.1)

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

requirements.txt

@@ -22,7 +22,7 @@ markdown2==2.4.0
 mccabe==0.6.1
 mistune==0.8.4
 mysqlclient==2.0.3
-Pillow==8.1.0
+Pillow==8.1.1
 pycparser==2.20
 Pygments==2.8.0
 pylint==2.7.1