Update actions/checkout action to v4 (#46)

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

.github/workflows/build.yml

@@ -17,7 +17,7 @@ jobs:
         python-version: ['3.8', '3.9', '3.10', '3.11']
     steps:
       - name: Checkout 🛎️
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }} 🔧
         uses: actions/setup-python@v4
         with: