add prettier

packages/artplayer-template/vue2.js/README.md

@@ -1,24 +1,29 @@
 # hello-world
 
 ## Project setup
+
 ```
 npm install
 ```
 
 ### Compiles and hot-reloads for development
+
 ```
 npm run serve
 ```
 
 ### Compiles and minifies for production
+
 ```
 npm run build
 ```
 
 ### Lints and fixes files
+
 ```
 npm run lint
 ```
 
 ### Customize configuration
+
 See [Configuration Reference](https://cli.vuejs.org/config/).