CI is broken for community contributions

[stof]

the CI jobs seems to be relying on github secrets to be present. But those secrets are not exposed in pull_request jobs for untrusted PRs (i.e. PRs coming from forks) to avoid the risk of a malicious PR leaking the secret.
See https://github.com/heroku/heroku-buildpack-php/actions/runs/9665966313/job/26664478221?pr=738 for the result of such CI job.

This creates a confusing experience for contributors.

[dzuelke]

Right, but... what do you suggest we do about it? ;)

[stof]

Well, maybe those CI jobs requiring secrets should be skipped when secrets are not available instead of reporting weird failures.