chore(docs): Configure Volta to use Node 22.21.1 and pnpm 9.4.0 (#69110)

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: ian.alton@airbyte.io <ian.alton@airbyte.io>

docusaurus/.npmrc

@@ -0,0 +1 @@
+engine-strict=true

docusaurus/.nvmrc

@@ -1 +1 @@
-18.15.0
+22.21.1

docusaurus/package.json

@@ -3,7 +3,11 @@
   "version": "0.0.0",
   "private": true,
   "volta": {
-    "node": "18.15.0"
+    "node": "22.21.1",
+    "pnpm": "9.4.0"
+  },
+  "engines": {
+    "node": ">=20 <25"
   },
   "scripts": {
     "prepare-registry-cache": "node src/scripts/prepare-registry-cache.js",