checkout not overriding GITHUB_SHA

[bakoontz2]

When this action is invoked, the workspace SHA is no longer the same as the SHA of the triggering workflow, and therefore GITHUB_SHA is no longer correct.

[cory-miller]

It's not intended to do this. The docs specify the GITHUB_SHA is tied to the sha that triggered the workflow.

https://docs.github.com/en/actions/learn-github-actions/contexts#github-context

If you need the sha from the checkout step, you should use an environment variable to track it.