[Doc]: Add docs on how sapling integrates with CI/CD systems?

[antspy]

Hi,

I am reading through the docs, but I cannot find a mention on how Sapling PRs integrates with CI/CD systems.

Let's take for example github actions - as the docs mention, github PR review UI is confused by the sapling format, so much so that people should use reviewstack. Ok, this makes sense.

But PRs are also tightly related to CI/CD. For example, how to I modify the CI running on github actions, to ensure that it works properly with sapling - i.e. that every new update to a PR / amending a commit will result in tests being run?

Maybe this is trivial to do, but I just thought it would be nice to have some documentation about it :)