chore: Update express dependency to version 5.2.1 (GoogleCloudPlatform#4205)

Co-authored-by: Jennifer Davis <sigje@google.com>

Author: LukeSchlangen

run/helloworld/package.docs.json

@@ -14,6 +14,6 @@
   "author": "Google LLC",
   "license": "Apache-2.0",
   "dependencies": {
-    "express": "^4.17.1"
+    "express": "^5.2.1"
   }
 }