ci: bump checkout action to v4

Due to the transition from Node 16 to Node 20, the checkout action
needs to be updated to v4.

More info: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/

Signed-off-by: Geyslan Gregório <geyslan@gmail.com>

.github/workflows/codeql.yml

@@ -32,7 +32,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v2