message: Update README.md
  fix start script
diff: @@ -113,7 +113,7 @@ npm install npm-run-all --save-dev
  + "type-check:watch": "npm run type-check -- --watch",
  - "start": "rimraf dist && parcel ./src/index.html --open"
  + "start:dev": "rimraf dist && parcel ./src/index.html --open",
  -+ "start": "run-p -l type-check:watch && start:dev"
  ++ "start": "run-p -l type-check:watch start:dev"
  },
  ```
  