update CI workflow to use actions/setup-python@v5

Author: Michael-J-Ward

.github/workflows/CI.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ${{ matrix.os }}-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-python@v2
+      - uses: actions/setup-python@v5
         with:
           python-version: "3.10"
           cache: "pip"