Bump actions/setup-python from 2 to 5

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 2 to 5.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v2...v5)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/docs.yml

@@ -14,7 +14,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Set up Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v5
         with:
           python-version: "3.10"
       - name: Install pydoctor

.github/workflows/python-distributions.yml

@@ -15,7 +15,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-python@v3
+      - uses: actions/setup-python@v5
       - name: Install native dependencies (Ubuntu)
         run: sudo apt-get update && sudo apt-get install -y libgpgme-dev libgpg-error-dev
         if: "matrix.os == 'ubuntu-latest'"
@@ -56,7 +56,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-python@v3
+      - uses: actions/setup-python@v5
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip

.github/workflows/pythontest.yml

@@ -19,7 +19,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install native dependencies (Ubuntu)