Update actions/setup-python action to v6

Author: renovate[bot]

.github/workflows/docs.yml

@@ -26,7 +26,7 @@ jobs:
         uses: ./.github/actions/get-metadata
 
       - name: 🐍 Setup Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: "3.13"
           cache: pip