Allow pat tokens

[cd-Barnes]

Hey folks, considering more organizations are choosing to force the use of the new fine-grained access tokens, I took a stab at implementing the feature. It's working well on our end. Lmk what you think.

Basically I'm solving this with a new var: github-token-type. If this value is not specified, or classic, then we'll use the old --token arg. If the user passes fine-grained, then we will use the --pat arg that allows the use of fine-grained tokens.

Note that this change also includes the work done in #127. Simply because we needed both fixes. However I'm happy to leave that out and allow discussion to continue over there if that's preferable.

Fixes #160, builds upon #127