message: fix Select[multipie] with OptGroup will cause error.
diff: @@ -8,6 +8,9 @@ export function getValuePropValue(child) {
  if (child.key) {
  return child.key;
  }
  + if (child.type && child.type.isSelectOptGroup && props.label) {
  + return props.label;
  + }
  throw new Error(`no key or value for ${child}`);
  }
  