fix: package.json & package-lock.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-ENGINEIO-3136336

Author: snyk-bot

package-lock.json

@@ -155,7 +155,7 @@
     "sequelize": "^6.29.0",
     "sequelize-noupdate-attributes": "^1.0.0",
     "serve-index": "^1.9.1",
-    "socket.io": "^2.3.0",
+    "socket.io": "^2.5.0",
     "sqlite3": "^5.1.5",
     "svg-captcha": "^1.4.0",
     "swagger-ui-express": "^4.1.4",