docs: adjust static resource path

docs/site/release.sh

@@ -1,8 +1,4 @@
 #!/usr/bin/env sh
 vant-cli build-site
 
-superman-cdn /vant ./site/*.js
-
-rm -rf site/*.js
-
 gh-pages -d site --add --dest v3

vant.config.js

@@ -6,7 +6,7 @@ module.exports = {
     site: {
       publicPath:
         (typeof window === 'undefined' && process.env.PUBLIC_PATH) ||
-        'https://b.yzcdn.cn/vant/',
+        '/vant/v3/',
     },
     vetur: {
       tagPrefix: 'van-',