Star event is missing events

[jloh]

Hi all. The Star event is missing the sender, repository and organization fields that come in the webhook payload from GitHub:

go-github/github/event_types.go

Lines 909 to 919 in b3962ed

	// StarEvent is triggered when a star is added or removed from a repository.
	// The Webhook event name is "star".
	//
	// GitHub API docs: https://docs.github.com/en/developers/webhooks-and-events/webhook-events-and-payloads#star
	type StarEvent struct {
	// Action is the action that was performed. Possible values are: "created" or "deleted".
	Action *string `json:"action,omitempty"`
	// StarredAt is the time the star was created. It will be null for the "deleted" action.
	StarredAt *Timestamp `json:"starred_at,omitempty"`
	}

I'm happy to make the changes to this type myself if a PR would be accepted.

Thanks for the excellent library! It does absolutely everything!

[gmlewis]

Thank you, @jloh !
It is yours. 😁

[gmlewis]

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