ci: make "create cache" a reusable workflow

[romanc]

Description

Recent (planned) downtime of NCCS portal showed a whole in our translate test data caching strategy. When we run pySHiELD tests as re-usable workflow in e.g. NDSL tests, we don't cache the translate test data. To do so, we can "upgrade" the "create cache" workflow to be re-usable such that we can call it from e.g. NDSL when we create the cache there.

GHA doesn't provide a way to detect workflow_call as an event (e.g. github.event will be workflow_dispatch in that case, which is the same as for a manual dispatch). We thus create an artificial input in case the workflow is called from another workflow. That way we know. The artificial input has a default value such that we don't need to set it from the calling workflow.

How Has This Been Tested?

Tested on my fork, e.g. romanc/NDSL#5.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation: N/A
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules
• New check tests, if applicable, are included: N/A
• Targeted model, if this change was triggered by a model need/shortcoming: N/A

[romanc]

/cc @twicki for some reason I can't tag you as a reviewer

[fmalatino]

/cc @twicki for some reason I can't tag you as a reviewer

I just added him as a contributor. Going forward he should be accessible.

[romanc]

/cc @twicki for some reason I can't tag you as a reviewer

I just added him as a contributor. Going forward he should be accessible.

Thanks, Frank!

[twicki]

Nice!

[romanc]

With everybody's approval, can we get this one merged? The merging order for these PRs is

1. pySHiELD: this one
2. pyFV3: ci: make "create cache" a reusable workflow pyFV3#91
3. NDSL: ci: create cache for translate test data NDSL#279