[FEAT] `secrets.GITHUB_TOKEN` doesn't work with GitHub auth engine

Is your feature request related to a problem? Please describe. secrets.GITHUB_TOKEN cannot be used to authenticate to the GitHub secrets engine.

Describe the solution you’d like The secrets.GITHUB_TOKEN is able to be exchanged for a Vault token.

Additional context It seems Vault wants to call https://api.github.com/user for the token that was passed to the auth engine. But the token isn’t scoped to that API, and returns GET https://api.github.com/user: 403 Resource not accessible by integration.

[steveteuber]

We also assumed that this is working, because the ${{ secrets.GITHUB_TOKEN }} is used in the examples:

with:
  url: https://vault.mycompany.com:8200
  method: github
  githubToken: ${{ secrets.GITHUB_TOKEN }}
  caCertificate: ${{ secrets.VAULTCA }}

https://github.com/hashicorp/vault-action/blob/master/README.md#authentication-method

[jasonodonnell]

Closing since this is documented and a known limitation of Vault’s GH auth method.