Update node version in GitHub Actions CI

Address GitHub Actions warning: The following actions uses node12 which is deprecated and will be forced to run on node16: actions/setup-node@v2. For more info: https://github.blog/changelog/2023-06-13-github-actions-all-actions-will-run-on-node16-instead-of-node12-by-default/

.github/workflows/run-tests.yml

@@ -51,7 +51,7 @@ jobs:
         with:
           bundler-cache: true
       - name: Setup Node
-        uses: actions/setup-node@v2
+        uses: actions/checkout@v4
         with:
           node-version: 16
       - name: Install PostgreSQL