Bump tox from 3.19.0 to 3.20.1 (#7863)
* Bump tox from 3.19.0 to 3.20.1
* Bump tox version in Dockerfile
Bumps [tox](https://github.com/tox-dev/tox) from 3.19.0 to 3.20.1.
- [Release notes](https://github.com/tox-dev/tox/releases)
- [Changelog](https://github.com/tox-dev/tox/blob/master/docs/changelog.rst)
- [Commits](https://github.com/tox-dev/tox/compare/3.19.0...3.20.1)
Signed-off-by: dependabot-preview[bot] <[email protected]>
Signed-off-by: aiordache <[email protected]>