Enable ppc64le

Previously closed discussion: https://github.com/actions/setup-python/issues/613

Description:
Build python binaries for ppc64le and enable support for ppc64le in this repo.

Justification:
We recently launched GitHub Actions so open source projects can use runners on our Power and Z hardware. At this point, we are onboarding projects to use our GitHub actions service. Here is a blog post about our announcement and our official GitHub repo is located here.

This would greatly benefit a lot of open source communities to have the python action runner be supported on ppc64le. My goal is to eliminate inconsistencies with ppc64le and have parity with other archs (like with our newly released github actions).

Are you willing to submit a PR?
Yes absolutely. We can assist with any development, testing, and other needs if this feature request can be included in a roadmap.

まず actions/setup-python#613 の以前にクローズされたディスカッションを読み、次にこのリポジトリの build と release のエントリポイントを特定します。issue ではファイルもテストも指定されていません。ppc64le 用の Python バイナリがビルドされ、action がそのアーキテクチャをサポートし、新しいパスのカバレッジが追加されれば完了です。