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!

Start by reviewing the repository’s existing GitHub Actions workflows and the IBM actionspz documentation linked in the issue. Determine how the ppc64le runner should be added to the current CI configuration; done means the relevant CI jobs run successfully on ppc64le without disrupting existing platforms.