message: build: add storybook script
diff: "prerelease": "yarn build",
  "pretest": "yarn lint",
  "release": "yarn prepare-release && lerna publish --exact && yarn postrelease",
  - "postrelease": "lerna run deploy-demo"
  + "postrelease": "lerna run deploy-demo",
  + "storybook": "cd packages/superset-ui-plugins-demo && yarn storybook"
  },
  "repository": "https://github.com/apache-superset/superset-ui-plugins.git",
  "keywords": [
  