Fix lint error

Author: Brandon Dail

packages/react-test-renderer/src/__tests__/ReactShallowRenderer-test.js

@@ -1457,7 +1457,7 @@ describe('ReactShallowRenderer', () => {
 
   it('should handle memo', () => {
     const Foo = () => {
-      <div>Foo</div>;
+      return <div>Foo</div>;
     };
     const MemoFoo = React.memo(Foo);
     const shallowRenderer = createRenderer();