Add missing UID in SubjectAccessReviewSpec

WebhookAuthorizer's Authorize should send *all* the information
present in the user.Info data structure. We are not sending the
UID currently.

pkg/registry/authorization/util/helpers.go

@@ -64,6 +64,7 @@ func AuthorizationAttributesFrom(spec authorizationapi.SubjectAccessReviewSpec)
 	userToCheck := &user.DefaultInfo{
 		Name:   spec.User,
 		Groups: spec.Groups,
+		UID:    spec.UID,
 		Extra:  convertToUserInfoExtra(spec.Extra),
 	}