docs(@vant/cli): changelog v6.0.0 (#11619)

packages/vant-cli/docs/config.md

@@ -219,7 +219,7 @@ If you need to configure some vite plugins, please create a `vite.config.ts` fil
 ### build.packageManager
 
 - Type: `'npm' | 'yarn' | 'pnpm'`
-- Default: `undefined`
+- Default: `yarn`
 
 `npm` package manager.
 

packages/vant-cli/docs/config.zh-CN.md

@@ -221,7 +221,7 @@ module.exports = {
 ### build.packageManager
 
 - Type: `'npm' | 'yarn' | 'pnpm'`
-- Default: `undefined`
+- Default: `yarn`
 
 指定使用的包管理器。