Feature: Improve static-builds.yml on pull_request (Add link to artifacts)

[erikmd]

Related project scope(s): GHA and PRs

The problem

The artifacts' URL is not easy to find.

(except at release time, of course)

Wanted solution

• Add a step in static-builds.yml
• using bash / curl commands or so
• to append links in PR's status summary for the 7 artifacts: {learn-ocaml-client,learn-ocaml,learn-ocaml-server}×{linux,darwin},
  and the zip archive.

Additional context

• Use this REST entrypoint? https://docs.github.com/en/rest/commits/statuses#create-a-commit-status
• See also:
  https://github.com/coq/bot/blob/e278b31632aa0bfad0934b028f82324bfd2eb486/src/actions.ml#L210-L228
  https://github.com/coq/bot/blob/e278b31632aa0bfad0934b028f82324bfd2eb486/bot-components/GitHub_mutations.ml#L203-L211

[erikmd]

Algo (given ocaml-sf/learn-ocaml is a public repo):

curl \
-H "Accept: application/vnd.github+json" \
"https://api.github.com/repos/${{ github.repository }}/actions/runs/${{ github.run_id }}/artifacts" \
| jq '[.artifacts | .[] | {"id": .id, "name": .name, "up": .updated_at, "exp": .expires_at, "dl_fyi": .archive_download_url}]'

# curl -D -  \
# -H "Accept: application/vnd.github+json" \
# -H "Authorization: Bearer $TOKEN" \  # (PAC, public repo)
# "$dl_fyi"

curl \
-H "Accept: application/vnd.github+json" \
"https://api.github.com/repos/ocaml-sf/learn-ocaml/actions/runs/${{ github.run_id }}" \
| jq '.check_suite_id'

echo https://github.com/ocaml-sf/learn-ocaml/suites/$suite_id/artifacts/$art_id

echo Status description: name; should login to download the github artifact; timestamps with `date` rendering

Use https://docs.github.com/en/rest/commits/statuses#create-a-commit-status