Bump setup-node action

Author: dylanhand

.github/workflows/docsygen.yml

@@ -30,7 +30,7 @@ jobs:
           which realpath
 
       - name: Setup Node.js for Slidev
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: '20'