Update actions/setup-python action to v6 (#78)

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

Author: renovate[bot]

.github/workflows/main.yml

@@ -38,7 +38,7 @@ jobs:
         python-version: ['3.13', '3.12', '3.11', '3.10']
     steps:
     - uses: actions/checkout@v5
-    - uses: actions/setup-python@v5
+    - uses: actions/setup-python@v6
       with:
         python-version: '${{ matrix.python-version }}'
     - name: Get Poetry version from .mise.toml