fix: skeleton cannot dispaly without children

Author: AlbertAZ1992

components/skeleton/Skeleton.tsx

@@ -161,7 +161,7 @@ const Skeleton = (props: SkeletonProps) => {
       </div>
     );
   }
-  return children as React.ReactElement;
+  return children ? children as React.ReactElement : null;
 };
 
 Skeleton.defaultProps = {

components/skeleton/__tests__/index.test.js

@@ -34,6 +34,11 @@ describe('Skeleton', () => {
     expect(wrapperSmall.render()).toMatchSnapshot();
   });
 
+  it('should display without children', () => {
+    const wrapper = mount(<Skeleton loading={false}></Skeleton>);
+    expect(wrapper.render()).toMatchSnapshot();
+  });
+
   it('should display children', () => {
     const wrapper = mount(<Skeleton loading={false}>{[1, 2, 3]}</Skeleton>);
     expect(wrapper.text()).toBe('123');