Chore: use GitHub Actions

[mysticatea]

What is the purpose of this pull request? (put an "X" next to item)

[X] Other, please explain: Trial GitHub Actions

What changes did you make? (Give an overview)

This PR set up GitHub Actions for CI.

GitHub Actions works on Azure that is the current our CI.

There are some cons:

• It doesn't provide build badge. (E.g., Azure Pipelines provide )
• It doesn't provide the detail of tests. (E.g., Azure Pipelines provide the Tests Tab)
• It doesn't provide the detail of code coverage. (E.g., Azure Pipelines provide the Code Coverage Tab)

Is there anything you'd like reviewers to focus on?

Do we want to switch CI platform?

[kaicataldo]

I'm supportive of switching over to GitHub actions 👍 Seems like we might be able to leverage them for other tasks as well.

[g-plane]

I think GitHub Actions provides badges. See an example: https://github.com/yarnpkg/berry/blob/master/README.md

[mysticatea]

@g-plane Thank you! I have added the badge, but it doesn't seem to exist until merged.

[platinumazure]

Thanks for putting this together, @mysticatea!

Are there any benefits to switching to GitHub Actions at this time? So far, I've only seen cons identified in this issue. 😄

[mysticatea]

I think the pro is that we don't need to depend on external services.

And in the future, I guess that we can aggregate CI and other workflows (commit message validator, release cycle monitor, "needs info" label handler, and auto-closer of issues) into GitHub Actions. If it was realized, probably we can reduce the maintenance cost of infrastructure.

[mysticatea]

TSC Summary

This PR switches our CI to GitHub Actions from Azure Pipelines.

Pros:

• We don't need to depend on external services for CI.
• I guess that we can aggregate CI and other workflows (commit message validator, release cycle monitor, "needs info" label handler, and auto-closer of issues) into GitHub Actions. If it was realized, probably we can reduce the maintenance cost of infrastructure.

Cons:

• It's still beta.
• It doesn't provide the detail of tests. (E.g., Azure Pipelines provide the Tests Tab)
• It doesn't provide the detail of code coverage. (E.g., Azure Pipelines provide the Code Coverage Tab)

TSC Question

Should we switch CI?

[mysticatea]

TSC Resolution: We add GitHub Actions beside with Azure Pipelines, then evaluate it. If GitHub Actions gets stable and we find that it's good enough, we will complete switching. Meeting Notes.

[mysticatea]

I have re-added files of Azure Pipelines.

[kaicataldo]

LGTM!