chore. fix description

package.json

 {
   "name": "react-native-agora",
   "version": "2.3.3-alpha.6",
-  "description": "声网Agora",
+  "description": "React Native around the Agora RTC SDKs for Android and iOS agora",
   "summary": "agora native sdk for react-native",
   "main": "lib/index.js",
   "scripts": {