Update actions/setup-python action to v6

Author: renovate[bot]

.github/workflows/unittest.yaml

@@ -10,7 +10,7 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - name: Setup Python
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: "3.13"
     - name: Install dependencies