docs: add CNAME

Author: tangjinzhou

scripts/gulpfile.js

@@ -56,6 +56,10 @@ function copyHtml() {
     path.join(cwd, 'site-dist/404.html'),
     fs.readFileSync(path.join(cwd, 'site/404.html')),
   );
+  fs.writeFileSync(
+    path.join(cwd, 'site-dist/CNAME'),
+    'vue.ant.design',
+  );
   rl.on('line', line => {
     if (line.indexOf('path:') > -1) {
       const name = line.split("'")[1].split("'")[0];