Bump actions/setup-python from 5 to 6 in the actions group

Bumps the actions group with 1 update: [actions/setup-python](https://github.com/actions/setup-python).


Updates `actions/setup-python` from 5 to 6
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](actions/setup-python@v5...v6)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/build-docs.yml

@@ -15,7 +15,7 @@ jobs:
     steps:
     - uses: actions/checkout@v5
     - name: Set up Python
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: 3.9
     - name: Install dependencies

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
     steps:
       - uses: actions/checkout@v5
       - name: Set up Python 3
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: 3
           cache: "pip"