docs: fix publicPath

packages/vant/docs/markdown/changelog.en-US.md

@@ -18,3 +18,5 @@ Vant follows [Semantic Versioning 2.0.0](https://semver.org/lang/zh-CN/).
 - Major version：including breaking changes and new features.
 
 ## Details
+
+TODO

packages/vant/docs/markdown/changelog.zh-CN.md

@@ -19,9 +19,9 @@ Vant 遵循 [Semver](https://semver.org/lang/zh-CN/) 语义化版本规范。
 
 ## 更新内容
 
-### unreleased
+### 4.0.0-alpha.0
 
-`2022-01-17`
+`2022-02-21`
 
 **Feature**
 

packages/vant/vant.config.mjs

@@ -7,7 +7,7 @@ export default {
     packageManager: 'pnpm',
     site: {
       publicPath:
-        (typeof window === 'undefined' && process.env.PUBLIC_PATH) || '/vant/',
+        (typeof window === 'undefined' && process.env.PUBLIC_PATH) || '/vant/v4',
     },
     vetur: {
       tagPrefix: 'van-',