build(actions): Use Node 20

Author: Brent Schmidt

.github/workflows/continuous-integration.yml

@@ -11,7 +11,7 @@ jobs:
     - uses: actions/checkout@v2
     - uses: actions/setup-node@v2
       with:
-        node-version: '16.x'
+        node-version: '20.x'
         cache: 'npm'
         registry-url: 'https://registry.npmjs.org'
         scope: '@oreillymedia'