Feature request: Support install nightly version

[hikouki-gumo]

Sometime our team wants to explore/prepare for new version release, then we want to install nightly version. Is it make sense to support that? I would love to draft a PR.

[roger-zhangg]

Thanks @hikouki-gumo for raising this issue and we always welcome contribution!

Support nightly release makes a lot sense to me. Our nightly release could be found at: https://github.com/aws/aws-sam-cli/releases/tag/sam-cli-nightly and please keep in mind nightly release is only supported with use-installer: true cause there's no PyPI nightly release to be found.

So the experience could be something like this

      - uses: aws-actions/setup-sam@v2
        with:
          use-installer: true
          version: nightly
          token: ${{ secrets.GITHUB_TOKEN }}

Let me know if there's anything you'd like to discuss