Bump bull from 3.20.1 to 3.21.0

Bumps [bull](https://github.com/OptimalBits/bull) from 3.20.1 to 3.21.0.
- [Release notes](https://github.com/OptimalBits/bull/releases)
- [Changelog](https://github.com/OptimalBits/bull/blob/develop/CHANGELOG.md)
- [Commits](https://github.com/OptimalBits/bull/compare/v3.20.1...v3.21.0

)

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