downgrade wechaty to 0.68

Paimon don't some features in wechat1.x (wechaty/puppet#158)

Author: zpaimon

docusaurus/docs/puppet-services/paimon.md

@@ -27,7 +27,7 @@ package.json
   "license": "Apache-2.0",
   "dependencies": {
     "qrcode-terminal": "^0.12.0",
-    "wechaty": "^1.0"
+    "wechaty": "^0.68"
   }
 }