Mount users local GCP application_default_credentials.json credentials in ACT container

[thomashutcheson-msm]

Hi

I would like to be able to run the workflow based of my own permissions stored in an application_default_credentials.json

I had thought I could pass them in via a my.secrete file and still leave the workflow looking the same as this:

      - name: google auth
        uses: google-github-actions/auth@v1
        with:
          credentials_json: ${{ secrets.SOME_SERVIC_ACCOUNT }}

but application default creds are different, so the alternative is to mount my creds to the container running locally for the ACT run.
I have something similar in a docker-compose file that mounts the var/secrets/google directory:

    volumes:
      - ${HOME}/.config/gcloud:/var/secrets/google

and sets an env of:
GOOGLE_APPLICATION_CREDENTIALS: /var/secrets/google/application_default_credentials.json

Might be missing something let me know if there is something I can try.