CI: Enable GitHub Actions CI for ppc64le (Power architecture) support

Hi team,

We’re reaching out to propose enabling CI support for the ppc64le (IBM Power) architecture in your repository, as part of a broader effort to ensure cross-platform compatibility in the scientific Python ecosystem.

We’re using a GitHub Actions (GHA)-based runner service provided and maintained by IBM to run jobs for the ppc64le architecture. This setup has already been successfully integrated into projects like:

✅ https://github.com/pyca/cryptography/pull/13130

✅ https://github.com/numpy/numpy/pull/29212

✅ https://github.com/coveragepy/coveragepy/pull/2121

We’d now like to propose enabling the GitHub Actions app in this repository to allow running CI jobs for ppc64le directly via GitHub Actions. This would support upstream compatibility and help ensure continued support for the Power architecture in uvloop.

Key Benefits:
🔒 Ephemeral and secure runners, isolated per job

🛠️ Maintained by IBM, requires no setup effort from your side

🔁 Integrates with existing GitHub Actions workflows

📚 Technical documentation and usage details:
https://github.com/IBM/actionspz/tree/main/docs

We’re happy to assist with the setup or provide any additional details the team may need.

Thanks so much!

先檢查儲存庫現有的 GitHub Actions 工作流程，以及 issue 中連結的 IBM actionspz 文件。確定應如何將 ppc64le runner 加入目前的 CI 設定；當相關 CI 工作能在 ppc64le 上成功執行，且不影響現有平台時，即表示完成。