Add Events API

[fenhl]

Support for the Events API would be nice.

[wayofthepie]

I started looking at this here https://github.com/XAMPPRocky/octocrab/compare/master...wayofthepie:events-api?expand=1. I've been using an extension on octocrab for this API for a while now anyway, so said I might as well clean it up and try contribute it back. Lots left to do, but should have a PR soon enough.

[XAMPPRocky]

Thank you for your issue! A PR is more than welcome.

[wayofthepie]

Just adding this to track what's done/left to do in the main models.

• CommitCommentEvent (seems to be a bug in the model, or a docs issue for this one, see Event API docs mention field which does not exist for CommitCommentEvent github/docs#3190)
• CreateEvent
• DeleteEvent (this is missing a field in the docs Missing field in Event API docs for DeleteEvent github/docs#3192)
• ForkEvent
• GollumEvent
• IssueCommentEvent
• IssuesEvent
• MemberEvent (docs have some issues here too Event API docs for MemberEvent changes are incorrect github/docs#3378)
• PublicEvent
• PullRequestEvent
• PullRequestReviewCommentEvent
• PushEvent
• ReleaseEvent
• SponsorshipEvent
• WatchEvent

Seems to be some undocumented event types also, at least the following:

• PullRequestReviewEvent (see Undocumented event "PullRequestReviewEvent" github/docs#2709)