Update GitHub workflow actions to Node.js 20

Author: cletusw

.github/workflows/npm-publish.yml

@@ -14,7 +14,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-node@v3
         with:
-          node-version: 16
+          node-version: 20
       - run: npm ci
       - run: npm run test:ci
 
@@ -25,7 +25,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-node@v3
         with:
-          node-version: 16
+          node-version: 20
           registry-url: https://registry.npmjs.org/
       - run: npm ci
       - run: npm publish