Bump actions/setup-python from 5 to 6 (backport of #1487) (#1493)

Author: mergify[bot]

.github/workflows/ci-format.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
     - uses: actions/checkout@v4
-    - uses: actions/setup-python@v5
+    - uses: actions/setup-python@v6
       with:
         python-version: 3.10.4
     - name: Install system hooks