Upgrade GitHub Action for Python setup to v5

Per actions/setup-python#1085

Author: gunthercox

.github/workflows/python-package.yml

@@ -32,7 +32,7 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v3
+      uses: actions/setup-python@v5
       with:
         python-version: ${{ matrix.python-version }}
         cache: 'pip'