Bump actions/setup-python action to v6 (#163)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/documentation.yml

@@ -29,7 +29,7 @@ jobs:
     steps:
     - uses: actions/checkout@v5
     - name: Set up Python
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: '3.13'
     - name: Install dependencies