update docsite workflow

.github/workflows/docsite.yml

@@ -24,10 +24,10 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-yarn-
 
-      - name: Use Node.js 16.x
+      - name: Use Node.js 18.x
         uses: actions/setup-node@v1
         with:
-          node-version: 16.x
+          node-version: 18.x
 
       - run: yarn install