docs: Add keywords

Author: fwh1990

package.json

@@ -2,6 +2,7 @@
   "name": "react-native-iconfont-cli",
   "version": "1.0.0",
   "main": "index.js",
+  "keywords": ["iconfont", "react-native", "react-native-iconfont", "icon", "icons", "iconfont.cn"],
   "repository": "git@github.com:fwh1990/react-native-iconfont-cli.git",
   "author": "范文华 <531362022@qq.com>",
   "license": "MIT",