GitHub Package Registry is now GitHub Packages

We’re renaming GitHub Package Registry (GPR) to GitHub Packages. This change is reflected on GitHub.com, in the APIs and webhooks:
– There is a new [PackageEvent](https://developer.github.com/v3/activity/events/types/#packageevent) in the Events API which replaces the existing event RegistryPackageEvent.
– There is a new package webhook which replaces the existing registry_package webhook.
– The GraphQL API schema is also changing to reflect the new name.