⬆️ Bump virtualenv from 20.2.2 to 20.4.2

Bumps [virtualenv](https://github.com/pypa/virtualenv) from 20.2.2 to 20.4.2.
- [Release notes](https://github.com/pypa/virtualenv/releases)
- [Changelog](https://github.com/pypa/virtualenv/blob/main/docs/changelog.rst)
- [Commits](pypa/virtualenv@20.2.2...20.4.2)

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