update dependencies (#6267)

Signed-off-by: hongming <coder.scala@gmail.com>

vendor/k8s.io/kube-openapi/pkg/schemaconv/smd.go

@@ -214,9 +214,6 @@ func makeUnion(extensions map[string]interface{}) (schema.Union, error) {
 		}
 	}
 
-	if union.Discriminator != nil && len(union.Fields) == 0 {
-		return schema.Union{}, fmt.Errorf("discriminator set to %v, but no fields in union", *union.Discriminator)
-	}
 	return union, nil
 }