Update actions/setup-python action to v6

Author: renovate[bot]

.github/workflows/release.yml

@@ -33,7 +33,7 @@ jobs:
         fetch-depth: 0  # unshallow fetch for setuptools-scm
 
     - name: Install Python 3.9
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: '3.13'
 

.github/workflows/run_tests.yml

@@ -28,7 +28,7 @@ jobs:
         echo "Reason for triggering: ${{ github.event.inputs.reason }}"
 
     - name: Set up Python
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: 3.13