Merge pull request #17521 from artursvonda/patch-1

[material-ui] Add missing methods for opening date picker dialog

types/material-ui/index.d.ts

@@ -942,6 +942,8 @@ declare namespace __MaterialUI {
             utils?: propTypes.utils;
         }
         export class DatePicker extends React.Component<DatePickerProps> {
+            focus(): void;
+            openDialog(): void;
         }
 
         interface DatePickerDialogProps {