pathogen-repo-ci: Support a continue-on-error pass thru

[tsibley]

Allows calling workflows to succeed even if the job in this called workflow fails. This is a workaround for the calling working being unable to specify continue-on-error itself.¹

Related-to: nextstrain/docker-base#148

¹ https://docs.github.com/en/actions/using-workflows/reusing-workflows#supported-keywords-for-jobs-that-call-a-reusable-workflow

Testing

• Checks pass

[tsibley]

This works. The (intentionally) failed call of pathogen-repo-ci with continue-on-error: true doesn't tank the calling workflow:

and the UI also highlights the failures:

[victorlin]

I wish the GitHub UI had some sort of indication on the commit level (2nd pic above, 1st arrow) that only continue-on-errors have failed. Mostly for this repo: since we expect test-pathogen-repo-ci-failure to always fail, the homepage will always show ❌ which needs an extra click to verify that it's just the one expected failure.

But, not a big deal. The ❌ should be useful on other repos.

[tsibley]

Yeah. We could remove the test-pathogen-repo-ci-failure job from this repo's CI if it gets in the way too much. It's really only testing that the GitHub Actions behaviour works as expected. That is, I don't think we need to continually test that our continue-on-error: ${{ inputs.continue-on-error }} line remains in working order.