build(deps-dev): bump virtualenv from 20.26.3 to 20.26.6

Bumps [virtualenv](https://github.com/pypa/virtualenv) from 20.26.3 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@20.26.3...20.26.6)

---
updated-dependencies:
- dependency-name: virtualenv
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

packages/requirements-dev.txt

@@ -96,6 +96,6 @@ tox==4.18.0 ; python_version >= "3.8" and python_version < "4.0"
 typing-extensions==4.12.2 ; python_version >= "3.8" and python_version < "3.11"
 tzdata==2024.1 ; python_version >= "3.8" and python_version < "4.0" and sys_platform == "win32"
 urllib3==2.2.2 ; python_version >= "3.8" and python_version < "4.0"
-virtualenv==20.26.3 ; python_version >= "3.8" and python_version < "4.0"
+virtualenv==20.26.6 ; python_version >= "3.8" and python_version < "4.0"
 wcwidth==0.2.13 ; python_version >= "3.8" and python_version < "4.0"
 zipp==3.20.1 ; python_version >= "3.8" and python_version < "3.10"