chore(deps): update actions/setup-python action to v6

Author: renovate[bot]

.github/workflows/ci.yaml

@@ -25,7 +25,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: ${{ matrix.python-version }}
 
@@ -82,7 +82,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Set up Python
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: '3.13'  # Use 3.13 until bandit supports 3.14
 
@@ -117,7 +117,7 @@ jobs:
         fetch-depth: 0  # Needed for setuptools_scm
 
     - name: Set up Python
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: '3.14'
 
@@ -157,7 +157,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Set up Python
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: '3.14'