ci: update actions/checkout (pypi)

Author: rodrigomelo9

.github/workflows/pypi.yaml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout code
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
     - name: Set up Python
       uses: actions/setup-python@v2
       with: