Update actions/checkout action to v4

Author: renovate[bot]

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ jobs:
         python-version: [ '3.7', '3.8', '3.9', '3.10' ]
     name: Python ${{ matrix.python-version }} sample
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Setup python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with: