Update GitHub Checkout action to v4

Author: gilzoide

.github/workflows/test.yml

@@ -6,7 +6,7 @@ jobs:
     name: Run tests
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
         with:
           submodules: true
       - name: Build