Update actions/setup-python action to v6

Author: renovate[bot]

.github/workflows/toolkit.yml

@@ -53,7 +53,7 @@ jobs:
         working-directory: ./docker
         run: docker build -t $IMAGE_NAME .
       - name: Setup python
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v6
         with:
           python-version: '3.14'
           cache: 'pip'