add all frontend files

node_modules/rc-select/lib/OptGroup.d.ts

@@ -0,0 +1,12 @@
+import type * as React from 'react';
+import type { DefaultOptionType } from './Select';
+export interface OptGroupProps extends Omit<DefaultOptionType, 'options'> {
+    children?: React.ReactNode;
+}
+export interface OptionGroupFC extends React.FC<OptGroupProps> {
+    /** Legacy for check if is a Option Group */
+    isSelectOptGroup: boolean;
+}
+/** This is a placeholder, not real render in dom */
+declare const OptGroup: OptionGroupFC;
+export default OptGroup;