fix(deps): update dependency openapi-backend to v5

Author: renovate[bot]

mock-server/package-lock.json

@@ -30,7 +30,7 @@
     "json-schema-ref-parser": "9.0.9",
     "js-yaml": "3.14.1",
     "morgan": "1.10.0",
-    "openapi-backend": "3.9.2",
+    "openapi-backend": "5.5.0",
     "source-map-support": "0.5.21",
     "which": "2.0.2"
   },