✨ Add instant docs deploy previews for PRs from forks

[tiangolo]

✨ Add instant docs deploy previews for PRs from forks.

This uses the new GitHub Actions event workflow_run.

The GitHub Action event is currently not very well documented, and it ended up requiring a new custom action to extract the original PR for that docs deployment. But this should help with previews for changes in docs (e.g. translations). Instead of the current workaround of previews triggered every hour, this should have a preview in a comment ready in about 1 minute.

[codecov]

Codecov Report

Merging #2244 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master     #2244   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          239       239           
  Lines         7079      7079           
=========================================
  Hits          7079      7079           

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[github-actions]

🚀 Deployed on https://5f95bb7c2b0149a7f7568b28--fastapi.netlify.app

[adriangb]

Hey @tiangolo, I was able to get this to work using pure workflows (here and here) and some existing actions. Not that this is any better than what you've got, just sharing options 😄

The main thing that helped in figuring out the workflow_run event (which as you say, isn't very well documented) is that you can do echo ${{ toJSON(github.event.workflow_run) }} to get all of the key/values in there.

[tiangolo]

Thanks @adriangb! Very interesting! 🤓

Sorry for the long delay! 🙈 I wanted to personally address each issue/PR and they piled up through time, but now I'm checking each one in order.