fix: Test with Node.js 20

Author: kriskowal

.github/workflows/test-getting-started.yml

@@ -11,10 +11,10 @@ jobs:
   getting_started:
     runs-on: ubuntu-latest
     steps:
-      - name: Use Node.js 18
+      - name: Use Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: '18'
+          node-version: '20'
       - name: Creating Your Dapp From a Template
         run: yarn create @agoric/dapp offer-up
       - name: Install dependencies