Add PyPy3.8

[henryiii]

Description:
Add support for PyPy3.8.

Justification:
PyPy used to support pypy3.6 and pypy3.7, then they just supposed pypy3.7, and now they support pypy3.7 and pypy3.8 (most recent release, 7.3.6). It would be nice to have pypy3.8, and I don't see that listed anywhere in this repo.

Are you willing to submit a PR?
Possibly, it it helps.

[mattip]

I think this is a documentation issue. The identifier pypy-3.8-v7.3.6 or pypy-3.8 should JustWork as long as it appears in the versions.json file. With that, maybe work is needed to cache it?

[nikita-bykov]

Hello @henryiii!
pypy-3.8 is already available via the setup-python action and as @mattip mentioned before you should use identifier like pypy-3.8 (Specifying a PyPy version).
Sample code:

- uses: actions/setup-python@v2
  with:
    python-version: 'pypy-3.8'
    architecture: 'x64'

This version is not preinstalled on our images, but if you'd like to suggest adding it, please create an issue in virtual-environments repository.
I'll close this issue, but if you have any questions feel free to ask.

[mattip]

See actions/runner-images#4345

[mattip]

Hmm, that was wrong. See actions/runner-images#4347

[henryiii]

I think you can get 7.3.7 with setup-python@v2, but you have to request it explicitly in the case of 3.7, since that's cached. I haven't tried yet, though I have started using pypy-3.8. Having it cached (and 3.7's cache bumped to 7.3.7) would be nice.