message: [Doc] update build:site script
diff: "build:entry": "node build/build-entry.js",
  "build:changelog": "vant-doc changelog ./changelog.generated.md",
  "build:lib": "node build/build-lib.js",
  - "build:site": "rm -rf docs/dist && cross-env NODE_ENV=production webpack --config build/webpack.doc.js && gh-pages -d docs/dist",
  + "build:site": "rm -rf docs/dist && cross-env NODE_ENV=production webpack --config build/webpack.doc.js && gh-pages -d docs/dist --add",
  "test": "jest",
  "test:watch": "jest --watch",
  "test:clear-cache": "jest --clearCache",
  