Update dependency socket.io to v4 [SECURITY]

Author: renovate[bot]

package.json

@@ -14,6 +14,6 @@
   "license": "ISC",
   "dependencies": {
     "express": "^4.14.0",
-    "socket.io": "^1.4.8"
+    "socket.io": "^4.0.0"
   }
 }