chore(actions): run docs actions on Node 16 to conform with the project (#26868)

Co-authored-by: Maxime Beauchemin <maximebeauchemin@gmail.com>

.github/workflows/superset-docs-verify.yml

@@ -18,6 +18,10 @@ jobs:
         with:
           persist-credentials: false
           submodules: recursive
+      - name: Set up Node.js 16
+        uses: actions/setup-node@v2
+        with:
+          node-version: '16'
       - name: yarn install
         run: |
           yarn install --check-cache