devel/py-virtualenv: Update to 21.1.0

• Update list of dependencies

ChangeLog:

• https://github.com/pypa/virtualenv/releases/tag/20.39.0
• https://github.com/pypa/virtualenv/releases/tag/20.39.1
• https://github.com/pypa/virtualenv/releases/tag/21.0.0
• https://github.com/pypa/virtualenv/releases/tag/21.1.0

Reported by: "github-actions[bot]" <notifications@github.com>