chore(deps): bump virtualenv from 20.30.0 to 20.31.1 (pyca#12861)

Bumps [virtualenv](https://github.com/pypa/virtualenv) from 20.30.0 to 20.31.1.
- [Release notes](https://github.com/pypa/virtualenv/releases)
- [Changelog](https://github.com/pypa/virtualenv/blob/main/docs/changelog.rst)
- [Commits](pypa/virtualenv@20.30.0...20.31.1)

---
updated-dependencies:
- dependency-name: virtualenv
  dependency-version: 20.31.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

ci-constraints-requirements.txt

@@ -337,7 +337,7 @@ uv==0.7.2 ; python_full_version >= '3.8'
     # via nox
 virtualenv==20.26.6 ; python_full_version < '3.8'
     # via nox
-virtualenv==20.30.0 ; python_full_version >= '3.8'
+virtualenv==20.31.1 ; python_full_version >= '3.8'
     # via nox
 webencodings==0.5.1 ; python_full_version < '3.8'
     # via bleach