fix(PlaceholderContainer): add component to index file (#1924)

Co-authored-by: Aleksandr Burobin <[email protected]>

src/components/index.ts

@@ -34,6 +34,7 @@ export * from './Pagination';
 export * from './Palette';
 export * from './UserLabel';
 export * from './PinInput';
+export * from './PlaceholderContainer';
 export * from './Popover';
 export * from './Popup';
 export * from './Portal';