docs: update the link of playground

Author: cloydlau

README.md

@@ -11,7 +11,7 @@
 </p>
 
 <p align="center">
-  <a href="https://cloydlau.github.io/demo/json-editor-vue.html"><img alt="playground" src="https://img.shields.io/badge/Playground-blue?color=9BE4E0"></a>
+  <a href="https://cloydlau.github.io/playground/json-editor-vue/"><img alt="playground" src="https://img.shields.io/badge/Playground-blue?color=9BE4E0"></a>
   <br>
   <a href="https://npmjs.com/package/json-editor-vue"><img alt="npm" src="https://img.shields.io/npm/v/json-editor-vue.svg?color=cb3837"></a>
   <a href="https://jsr.io/@cloydlau/json-editor-vue"><img alt="jsr" src="https://jsr.io/badges/@cloydlau/json-editor-vue"></a>

docs/README.zh-CN.md

@@ -11,7 +11,7 @@
 </p>
 
 <p align="center">
-  <a href="https://cloydlau.github.io/demo/json-editor-vue.html"><img alt="playground" src="https://img.shields.io/badge/Playground-blue?color=9BE4E0"></a>
+  <a href="https://cloydlau.github.io/playground/json-editor-vue/"><img alt="playground" src="https://img.shields.io/badge/Playground-blue?color=9BE4E0"></a>
   <br>
   <a href="https://npmjs.com/package/json-editor-vue"><img alt="npm" src="https://img.shields.io/npm/v/json-editor-vue.svg?color=cb3837"></a>
   <a href="https://jsr.io/@cloydlau/json-editor-vue"><img alt="jsr" src="https://jsr.io/badges/@cloydlau/json-editor-vue"></a>