docs: redirect /zh-CN to /, Close umijs#8213, Close umijs#8181

Author: sorrycc

docs/README.md

@@ -9,3 +9,4 @@ import Footer from './components/Footer/Footer';
 <WhoIsUsing />
 <Contributing />
 <Footer />
+

global.ts

@@ -0,0 +1,4 @@
+// Redirect /zh-CN to /
+if (location.pathname.startsWith('/zh-CN')) {
+  location.pathname = '/';
+}