Bump checkout version to avoid warnings about nodejs being deprecated

run-tests
The following actions uses node12 which is deprecated and will be forced to run on node16: actions/checkout@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

@@ -13,7 +13,7 @@ jobs:
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: Install deps
         run: |