Add ability to pass a bearer token from an GitHub App instead of a personal access token.

[doodzik]

I'm using a GitHub app to make API requests, which gives allows me to set finer permissions than through a personal access token. As I was looking through the code I didn't see the ability to pass a bearer token to the tool.

Would you merge the feature to authenticate with a bearer token if I would build it out?

[jonatas]

@doodzik sorry for the late reply. Feel free to build it and send the PR. As the actual needs are simply fetching the team names and user names that is enough for the actual checker but if it's useful feel free to add this new authentication mode.