[Footer] add current year dynamically (#8850)

* docs: fix English README link

* docs(lang): add countries' flags

* docs(lang): add countries' flags

* feat(footer): add current year dynamically

src/components/Footer/index.tsx

@@ -9,9 +9,11 @@ export default () => {
     defaultMessage: '蚂蚁集团体验技术部出品',
   });
 
+  const currentYear = new Date().getFullYear();
+
   return (
     <DefaultFooter
-      copyright={`2020 ${defaultMessage}`}
+      copyright={`${currentYear} ${defaultMessage}`}
       links={[
         {
           key: 'Ant Design Pro',