chore(deps): update actions/setup-python action to v6

Author: renovate[bot]

.github/workflows/flake8.yml

@@ -12,7 +12,7 @@ jobs:
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4
 
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: 3.8