ci: actually bump the version as described

Author: james-garner-canonical

.github/workflows/test.yaml

@@ -133,7 +133,7 @@ jobs:
       - name: Check out code
         uses: actions/checkout@v3
       - name: Setup Python
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python }}
       - name: Setup operator environment