chore(ci): upgrade Node.js version from 16 to 20 in workflows

Author: angelcaamal

.github/workflows/test.yaml

@@ -40,7 +40,7 @@ jobs:
         service_account: 'kokoro-system-test@long-door-651.iam.gserviceaccount.com'
         create_credentials_file: 'true'
         access_token_lifetime: 600s
-    - uses: actions/setup-node@8f152de45cc393bb48ce5d89d36b731f54556e65 # v4.2.4
+    - uses: actions/setup-node@8f152de45cc393bb48ce5d89d36b731f54556e65 # v4.0.0
       with:
         node-version: 20
     - name: Get npm cache directory