Ease Into Compatibility

This release simply exposes additional previously internal functions used to convert OpenAPI 3.0 compatible documents into OpenAPI 3.1 compatible documents.

These newly public functions are not intended to be used directly but using them directly can help downstream maintainers migrate code from the OpenAPIKit30 module to the OpenAPIKit module gradually instead of all at once so they are being exposed publicly for a limited time. They will be made private in a future release, likely either the final OpenAPIKit 3.0.0 release or perhaps not until the OpenAPIKit 4.0.0 releases. Regardless, they aren't to be relied upon for code that is intended to be permanent.