Update Node.js requirement to v20 for Docusaurus 3.9.2

Author: tobihagemann

.github/workflows/deploy.yml

@@ -18,7 +18,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: '18'
+          node-version: '20'
           cache: 'npm'
       - name: Install dependencies
         run: npm ci

package.json

@@ -45,6 +45,6 @@
     ]
   },
   "engines": {
-    "node": ">=18.0"
+    "node": ">=20.0"
   }
 }