fix: upgrade express-rate-limit from 5.0.0 to 5.5.1

Snyk has created this PR to upgrade express-rate-limit from 5.0.0 to 5.5.1.

See this package in npm:
https://www.npmjs.com/package/express-rate-limit

See this project in Snyk:
https://app.snyk.io/org/klemek/project/81af650f-8c8e-4116-b289-95415c85d8a7?utm_source=github&utm_medium=referral&page=upgrade-pr

package.json

@@ -8,7 +8,7 @@
     "body-parser": "^1.19.0",
     "ejs": "^3.1.6",
     "express": "^4.17.1",
-    "express-rate-limit": "^5.0.0",
+    "express-rate-limit": "^5.5.1",
     "fa-diagrams": "^1.0.3",
     "mathjax-node": "^2.1.1",
     "ncp": "^2.0.0",