message: update Cascader i18n
diff: @@ -457,7 +457,8 @@ class Cascader extends React.Component<CascaderProps, CascaderState> {
  'esc'
  ]);
  - const getOptionsAndDropdownMenuColumnStyle = Locale => {
  + const getOptionsAndOthers = Locale => {
  + let { notFoundContent = Locale.notFoundContent, placeholder = Locale.placeholder } = this.props;
  let options = props.options;
  if (state.inputValue) {
  options = this.generateFilteredOptions(prefixCls, Locale);
  @@ -484,11 +485,15 @@ class Cascader extends React.Component<CascaderProps, CascaderState> {
  return {
  options,
  dropdownMenuColumnStyle,
  + notFoundContent,
  + placeholder
  };
  }
  const label = this.getLabel();
  - const getInput = Locale => children || (
  + const getInput = Locale => {
  + let { placeholder = Locale.placeholder } = this.props;
  + return children || (
  <span style={style} className={pickerCls}>
  <span
  className={`${prefixCls}-picker-label`}
  @@ -500,7 +505,7 @@ class Cascader extends React.Component<CascaderProps, CascaderState> {
  {...inputProps}
  ref={this.saveInput}
  prefixCls={inputPrefixCls}
  - placeholder={value && value.length > 0 ? undefined : (placeholder || Locale.placeholder)}
  + placeholder={value && value.length > 0 ? undefined : placeholder}
  className={`${prefixCls}-input ${sizeCls}`}
  value={state.inputValue}
  disabled={disabled}
  @@ -515,6 +520,7 @@ class Cascader extends React.Component<CascaderProps, CascaderState> {
  <Icon type="down-fill" className={arrowCls} />
  </span>
  );
  + }
  return (
  <ConfigConsumer componentName="Cascader">
  @@ -523,10 +529,8 @@ class Cascader extends React.Component<CascaderProps, CascaderState> {
  return (<RcCascader
  {...props}
  {
  - ...getOptionsAndDropdownMenuColumnStyle(Locale)
  + ...getOptionsAndOthers(Locale)
  }
  - notFoundContent={notFoundContent || Locale.notFoundContent}
  - placeholder={placeholder || Locale.placeholder}
  value={value}
  popupVisible={state.popupVisible}
  onPopupVisibleChange={this.handlePopupVisibleChange}
  