Fix double scroll bars in IE11 & Edge, close #393

src/components/SiderMenu/index.js

@@ -129,7 +129,7 @@ export default class SiderMenu extends PureComponent {
           {...menuProps}
           onOpenChange={this.handleOpenChange}
           selectedKeys={this.getCurrentMenuSelectedKeys()}
-          style={{ margin: '16px 0', width: '100%' }}
+          style={{ padding: '16px 0', width: '100%' }}
         >
           {this.getNavMenuItems(this.menus)}
         </Menu>