fix(deps): update dependency socket.io to v2 [security]

Author: renovate-bot

09_NodeChatroom/package.json

@@ -11,7 +11,7 @@
     "express": "^4.0.0",
     "jade": "*",
     "mongodb": "^3.1.13",
-    "socket.io": "^1.0.6",
+    "socket.io": "^2.4.0",
     "stylus": "^0.49.1"
   }
 }