Enhanced Vault guides and fixed some wording.

README.md

@@ -6,7 +6,7 @@ This short guide provides step by step instructions how to replace a JSON key wi
 
 - `openssl` 3.x
 - `vault` (only for the Vault based CA in step 1a)
-- Node.js with `npm`
+- Node.js 24 or later with `npm`
 - `gcloud` authenticated as an administrator of the target project
 
 ## Configuration
@@ -150,6 +150,9 @@ Requesting the client certificate from a remote Vault server with a user account
 
 ```json
 {
+  "engines": {
+    "node": ">=24"
+  },
   "dependencies": {
     "yaml": ">=2.9.1"
   }