Address Node.js 16 actions are deprecated.

Message on the run page continued with

Please update the following actions to use Node.js 20: actions/checkout@v3.
For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.

.github/workflows/build-test.yaml

@@ -21,7 +21,7 @@ jobs:
           - 'quay.io/centos/centos:stream8'
           - 'quay.io/centos/centos:centos7'
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set the right OS in the Dockerfile
         run: sed -i "s#^FROM.*#FROM ${{ matrix.os }}#" tests/Dockerfile
       - name: Build image