tools: add HTML previews for PR containing doc changes

[aduh95]

For PR containing doc changes, the GitHub Actions workflow will push the built docs to the gh-pages branch so reviewers can have a preview of the changes without needing to pull the PR and build the docs locally. The commit that is pushed to gh-pages has a reference to the PR so the commit will appear on the GH web UI (so no need to comment I think).

You can see this PR in action on nodejs/node-auto-test#53.

Before this can land (if we do want to land it), the following needs to happen:

1. An empty git tree should be pushed to the gh-pages branch.
2. GitHub Pages should be activated on this repo (this should happen automatically if the above is done by a repo admin).

Note that this PR is only adding files to the gh-pages, which will eventually get cluttered with old PR content. If you have an idea how we can manage, please chime in, otherwise we can leave the problem for our future selves to solve (reseting the gh-pages branch back to an empty git tree every few months should work well enough for our use case I think).

/cc @nodejs/tsc

[nodejs-github-bot]

Review requested:

• @nodejs/actions

[MoLow]

Note that this PR is only adding files to the gh-pages, which will eventually get cluttered with old PR content. If you have an idea how we can manage, please chime in, otherwise we can leave the problem for our future selves to solve (reseting the gh-pages branch back to an empty git tree every few months should work well enough for our use case I think).

we can remove the files when the PR is closed, that will probably cover the majority of PRS

[mcollina]

lgtm

[targos]

Could it be easily changed to push to a separate repository? I don't want myself and others who regularly fetch the whole repository to be affected by the increase in size.

[aduh95]

Could it be easily changed to push to a separate repository? I don't want myself and others who regularly fetch the whole repository to be affected by the increase in size.

Pushing to a different repo shouldn't be a problem. For my own curiosity, what's the use case for fetching the whole repository?

[tniessen]

I'd also prefer to use either a different repository or a different URL at least that more clearly indicates that these are not official docs, but rather (untrusted) previews.

[targos]

Could it be easily changed to push to a separate repository? I don't want myself and others who regularly fetch the whole repository to be affected by the increase in size.

Pushing to a different repo shouldn't be a problem. For my own curiosity, what's the use case for fetching the whole repository?

As a releaser and V8 maintainer, I regularly fetch everything to have up to date release, staging and canary-base branches.

[mcollina]

Overall I would prefer we used something on our infra, e.g. Vercel. While this work I feel it would create quite a bit of pain to folks.