Bumps [capybara](https://github.com/teamcapybara/capybara) from 3.20.2 to 3.21.0.
- [Release notes](https://github.com/teamcapybara/capybara/releases)
- [Changelog](https://github.com/teamcapybara/capybara/blob/master/History.md)
- [Commits](https://github.com/teamcapybara/capybara/compare/3.20.2...3.21.0)