Merge ci-github-hosted.yml into ci.yml using new, optional inputs.run-self-hosted

[CodeGat]

Closes #220

Background

Currently, build-ci uses two workflow files, ci.yml and ci-github-hosted.yml for self- and GitHub-hosted runners respectively.

This is due to small, previously irreconcilable differences in the jobs.*.containers section - specifically regarding the volumes section. The GitHub-hosted variant didn't need any volumes to function, but the self-hosted one did.

After chatting with GitHub Support, it was noted that it is indeed possible to reconcile these differences, by using a inputs.run-self-hosted input that turns the volume list into the expected list of volume defs if true, and empty lists if false.

The PR

• Add new, optional inputs.run-self-hosted that defaults to true
• jobs.*.runs-on is determined by inputs.run-self-hosted - either the self-hosted group or the default ubuntu-latest
• jobs.*.container.image is also determined by the new input - picking either the runner or upstream image
• jobs.*.container.volumes is the same - either the two required volumes for self-hosted, or dummy volumes for GitHub-hosted

Testing

Tested in ACCESS-NRI/access-test-component#15. Note that the failures are due to concretization issues with the manifest - it is the initialisation of the containers that is the important part.

Specifically:

• GitHub-hosted pulled the correct upstream image with dummy volumes in https://github.com/ACCESS-NRI/access-test-component/actions/runs/20053240115/job/57513298767 (see Initialise Containers step)
• Self-hosted pulled the correct runner image with two volumes in https://github.com/ACCESS-NRI/access-test-component/actions/runs/20051632302/job/57508743153 (see Initialise Containers step)

Other Implementations

In f2c8bd2, I used fromJson('[]') as the GitHub-hosted case, but that was a bit flaky, as it was doing:

- ${{ fromJson('[]') }}
- "[]"

Which meant under the hood docker --volume was silently ignoring the invalid volume definition (usually of the form HOST_PATH:CONTAINER_PATH:FLAGS). This works okay, but is flaky - docker or GitHub may throw errors for that in future.

[aidanheerdegen]

Nice work!