Bump actions/setup-python from 5 to 6

Bumps [actions/setup-python](https://github.com/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
...

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

Author: dependabot[bot]

.github/workflows/html-macos.yml

@@ -16,7 +16,7 @@ jobs:
       run: |
         brew install pandoc
     - name: Set up Python
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: 3
     - name: Double-check Python version

.github/workflows/linkcheck.yml

@@ -17,7 +17,7 @@ jobs:
       run: |
         $APT_INSTALL pandoc
     - name: Set up Python
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: "3"
     - name: Show Python version

.github/workflows/publish.yml

@@ -7,7 +7,7 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - name: Set up Python
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: "3"
     - name: Install "build"

.github/workflows/version-matrix.yml

@@ -52,7 +52,7 @@ jobs:
       run: |
         $APT_INSTALL pandoc librsvg2-bin
     - name: Set up Python ${{ env.PYTHON_VERSION }}
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: ${{ env.PYTHON_VERSION }}
     - name: Show Python version