CI: Add test job for Python 3.13

Python 3.13 is now in beta, thus is might be useful to start testing what works and what doesn't.

This PR adds a Python 3.13 job on Ubuntu.

.github/workflows/ci.yml

@@ -30,13 +30,16 @@ jobs:
  python-version: "3.12"
  pip-pre: "--pre" # Installs pre-release versions of pip dependencies
  name: "Pre-release dependencies"
+ - os: ubuntu-latest
+ python-version: "3.13"
 
  steps:
  - uses: actions/checkout@v4
  - name: Set up Python ${{ matrix.python-version }}
  uses: actions/setup-python@v5
  with:
  python-version: ${{ matrix.python-version }}
+ allow-prereleases: true
  - run: pip install uv
  - name: Install dependencies
  run: |