Update the version of the checkout Action used in the CodeQL workflow

Author: dscho

.github/workflows/codeql.yml

@@ -21,7 +21,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Install dependencies
         run: ci/install-dependencies.sh