Add support for GitHub tokens

[skyzyx]

Add support for GitHub tokens

[eregon]

Are you hitting these limits? What's the limit?

[skyzyx]

60 requests per hour for unauthenticated requests. It's 5,000 per hour for authenticated requests.

We're running inside GitHub Actions on GitHub Enterprise Server, and with the way that our CI nodes poke out through the corporate network, GitHub thinks all requests are coming from the same IP.

[eregon]

It'd be nice if we could automatically use the token, like actions/checkout does it in https://github.com/actions/checkout/blob/b4ffde65f46336ab88eb53be808477a3936bae11/action.yml#L24
But I'm not sure if that works for all actions.

In any case we need a token input, a PR to add this is welcome.