[Doc] deploy to github pages

build/webpack.doc.js

@@ -7,7 +7,7 @@ module.exports = Object.assign(config, {
   mode: 'production',
   output: {
     path: path.join(__dirname, '../docs/dist'),
-    publicPath: 'https://img.yzcdn.cn/zanui/vant/',
+    publicPath: 'https://youzan.github.io/vant/',
     filename: '[name].[hash:8].js',
     chunkFilename: 'async_[name].[chunkhash:8].js'
   }