Update actions/checkout action to v4 (#8)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

.github/workflows/code_check.yml

@@ -4,7 +4,7 @@ jobs:
     build:
         runs-on: ubuntu-latest
         steps:
-            - uses: actions/checkout@v2
+            - uses: actions/checkout@v4
             - name: Install modules
               run: npm ci
             - name: Run ESLint