Webhook MemberEvent Type is Missing Changes Object

[Tayo Oloyede]

The Member event type referenced here contains a changes object which is not reflected in the current MemberEvent Struct.

Confirmed that the changes object does get included in incoming webhook events.

{
    "event": "member",
    "payload": {
        "action": "added",
        "member": { },
        "changes": {
            "permission": {
                "to": "write"
            },
            "role_name": {
                "to": "maintain"
            }
        },
        "repository": { },
            
        },
        "organization": { }
}

Opened a pull request to add the missing object.