Schema Inaccuracy

These are some improvement I have found that could be made when comparing the current definition of the PingEvent to the definition in octokit/webhooks

• In the schema for the PingEvent webhook, no property is marked as required. (Innacuracy)
• The hook[config][content_type] property can be augmented using an enum, as indicated in it's description, the values would be json and form
• The hook[events] property can be augmented to be a oneOf, either an array with only the value * for all events, or an array with an enum of all possible webhook events, as done in octokit/webhooks
• The hook[type] property can be augmented to be an enum of the different webhook types, either Repository, Organization, or App
• The hook[config][insecure_ssl] property can be augmented to be an enum of either 0 or 1 as those are the only supported values

Expected

For the properties to be marked as required.
The other issues aren't critical, they are values that could be defined more explicitly.

Reproduction Steps

n/a