Integrate into Taichi release workflow

[rexwangcc]

No since we have plan to separate documentation articles (as well as generated API reference) from the main repo, we need to think carefully about how to craft/update the release workflow so it won't produce extra burden to the releaser(s) once we get rid of the rst docs in the main repo.

This is related to taichi-dev/taichi#1674

[yuanming-hu]

A random idea given most PRs/releases don't really need to change the articles: for those that do need an article update, maybe we can simply ask the main PR author to ensure he creates an article update PR is merged in taichi.graphics repo, and get it merged before merging the main PR in the taichi repo?

[rexwangcc]

we can simply ask the main PR author to ensure he creates an article update PR is merged in taichi.graphics repo, and get it merged before merging the main PR in the taichi repo?

That sounds like a great idea! Not sure how much burden this will bring to the review work, at least we could start with adding an action/TODO item to the PR template.