DEV: Bump virtualenv from 20.25.0 to 20.26.6 (#3050)

Bumps [virtualenv](https://github.com/pypa/virtualenv) from 20.25.0 to 20.26.6.
- [Release notes](https://github.com/pypa/virtualenv/releases)
- [Changelog](https://github.com/pypa/virtualenv/blob/main/docs/changelog.rst)
- [Commits](pypa/virtualenv@20.25.0...20.26.6)

---
updated-dependencies:
- dependency-name: virtualenv
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements/dev.txt

@@ -89,7 +89,7 @@ typing-extensions==4.7.1
     # via black
 urllib3==2.0.7
     # via requests
-virtualenv==20.25.0
+virtualenv==20.26.6
     # via pre-commit
 wheel==0.42.0
     # via