build: fix Node dependency in CI

Author: dm-p

.github/workflows/docusaurus_publish.yml

@@ -15,7 +15,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 18.x
+          node-version: 20
           cache: yarn
       - name: Test build
         run: |