add ghe support

[anden-dev]

Add support for GHE

https://docs.github.com/en/actions/learn-github-actions/variables

GITHUB_API_URL | Returns the API URL. For example: https://api.github.com.

[stevetoro]

Just attempted to use this action in a Github Enterprise workflow, encountered error due to the action trying to hit api.github.com.

@anden-dev were you able to find a way to use this action in GHE? Or did you decide on another package/strategy?

[anden-dev]

@stevetoro
Yes, I have this action with my proposed change running on GHE.

The variable is documented, you can check your GHE version's documentation or add a step like this to verify

   steps:
      - name: Echo GITHUB_API_URL
        run: echo $GITHUB_API_URL