ci: update checkout

Author: realstealthninja

.github/workflows/ctest.yml

@@ -12,10 +12,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Run unit tests
         uses: HorstBaerbel/[email protected]
-        # These are optional (defaults displayed)
         with:
           sourcedir: "."
           builddir: "build"