Property Validation: `format`

[everettraven]

The format constraint of a property automatically enforces specific validations on the property value (https://github.com/kubernetes/apiextensions-apiserver/blob/5714b0b58b88ea1b939e40a3602ee349ee4b57e7/pkg/apis/apiextensions/v1/types_jsonschema.go#L47-L73).

Changes to the format inherently changes these validations and is a breaking change for clients/users that have expectations based on the format constraint.