Update actions/setup-python action to v6

Author: solrbot

.github/workflows/renovate-changelog.yml

@@ -29,7 +29,7 @@ jobs:
           token: ${{ secrets.SOLRBOT_GITHUB_TOKEN }}
 
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: '3.x'