Bump six from 1.15.0 to 1.16.0

Bumps [six](https://github.com/benjaminp/six) from 1.15.0 to 1.16.0.
- [Release notes](https://github.com/benjaminp/six/releases)
- [Changelog](https://github.com/benjaminp/six/blob/master/CHANGES)
- [Commits](https://github.com/benjaminp/six/compare/1.15.0...1.16.0)

dios/requirements.txt

@@ -2,4 +2,4 @@ numpy==1.19.1
 pandas==1.2.4
 python-dateutil==2.8.1
 pytz==2021.1
-six==1.15.0
+six==1.16.0