return-license does not support the macos runner

[oshaughnessy]

Context

Running game-ci/unity-return-license@main on the macos-latest runner. Right now I get this error when I try to run it:

Error: Container action is only supported on Linux

Suggested solution

I would like the action to support running on macOS, so I can manually return a license allocated to the GitHub macOS runners that may consume licenses and fail to return them.

Considered alternatives

Tried returning the license on an Ubuntu runner, but I got blocked at #20 when exploring this avenue.

Additional details

See also:

• pro license isn't returned after successful completion on macos-latest unity-builder#358

[oshaughnessy]

I think this may be a limitation of GitHub. I'm still digging through docs, but the table here -- https://docs.github.com/en/actions/creating-actions/about-custom-actions#types-of-actions -- says that Docker actions are only supported on Linux, so I may just be out of luck for now.

[oshaughnessy]

Although... this gives me hope: https://docs.github.com/en/actions/creating-actions/metadata-syntax-for-github-actions#runsstepsuses. I think we may be able to create a composite action that runs locally if it's on macos or in Docker otherwise.