message: add vuepress scripts
diff: "test": "jest",
  "lint": "eslint ./src --fix",
  "flow": "flow",
  + "docs:dev": "vuepress dev docs",
  + "docs:build": "vuepress build docs",
  "build:locale": "babel-node build/locale.js",
  "build:umd": "babel-node build/umd.js",
  "build:esm": "babel-node build/esm.js",
  