Add support for authentication with JWT

A description of your problem or question

Greetings

First of all: Great job getting portion of the API working. I just encountered an issue today where this could have been helpful. Although I wonder how this pans out for large-scale automations where the token limit of 5000 will be hit (just had such a case today).

Is it possible to also use a GitHub App AccessToken? I know that in order to get that we need a signed JWT, but that could be accomplished with PowerShell I think, provided we provide a certificate.

Alternatively, is it possible to provide my own Bearer Token?