Bump certifi from 2020.6.20 to 2021.5.30
Bumps [certifi](https://github.com/certifi/python-certifi) from 2020.6.20 to 2021.5.30.
- [Release notes](https://github.com/certifi/python-certifi/releases)
- [Commits](https://github.com/certifi/python-certifi/compare/2020.06.20...2021.05.30)
Signed-off-by: dependabot-preview[bot] <[email protected]>