fix: a temporal workaround for the "virtualenv 20.33.0 breaks Poetry in GitHub Actions"

[Ki-Seki]

Description

Summary:

The upstream dependency virtualenv was upgraded to version 20.33.0, causing poetry to fail in executing commands based on the Python version in the virtual environment. This also likely caused the failure in locating the cache during the Set up Python ${{ matrix.python-version }} workflow step.

Related issues:

• virtualenv 20.33.0 breaks Poetry in GitHub Actions pypa/virtualenv#2931
• bug: poetry is using default python version instead of venv python as result of new version in virtualenv v20.33.0 python-poetry/poetry#10490
• Issues with poetry caching actions/setup-python#1167

Currently, the temporary workaround is to downgrade virtualenv from 20.33.0 to 20.32.

Reviewer: @fridayL @CaralHsi @J1awei-Yang

Checklist:

• I have performed a self-review of my own code | 我已自行检查了自己的代码
• I have commented my code in hard-to-understand areas | 我已在难以理解的地方对代码进行了注释
• I have added tests that prove my fix is effective or that my feature works | 我已添加测试以证明我的修复有效或功能正常
• I have added necessary documentation (if applicable) | 我已添加必要的文档（如果适用）
• I have linked the issue to this PR (if applicable) | 我已将 issue 链接到此 PR（如果适用）
• I have mentioned the person who will review this PR | 我已提及将审查此 PR 的人

[Copilot]

Pull Request Overview

This PR fixes a Windows workflow issue by installing a specific version of virtualenv to resolve compatibility problems with Poetry. The change addresses known issues with newer virtualenv versions that cause conflicts in Windows CI environments.

Key Changes

• Adds virtualenv version pinning to ensure compatibility with Poetry on Windows

Comments suppressed due to low confidence (1)

.github/workflows/python-tests.yml:48

• The virtualenv version 20.32 does not exist. The virtualenv package follows semantic versioning and the latest available versions are in the 20.x series but version 20.32 is not a valid release. Please verify the correct version number from the official virtualenv releases.

      run: pip install virtualenv==20.32