[material-ui][Button] Add target attribute to types

packages/mui-material/src/Button/Button.d.ts

@@ -60,6 +60,11 @@ export interface ButtonOwnProps {
    * If defined, an `a` element will be used as the root node.
    */
   href?: string;
+   /**
+   * The target for link when the button is clicked.
+   * @default '_blank'
+   */
+  target?: string,
   /**
    * The size of the component.
    * `small` is equivalent to the dense button styling.