ci: Add Python 3.13 (canonical#4567)

.github/workflows/unit.yml

@@ -14,29 +14,37 @@ jobs:
   unittests:
     strategy:
       matrix:
-        python-version: [ "3.7", "3.8", "3.9", "3.10", "3.11", "3.12" ]
-        toxenv: [ py3 ]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
+        toxenv: [py3]
         experimental: [false]
+        check-latest: [false]
+        continue-on-error: [false]
         include:
           - python-version: "3.6"
             toxenv: lowest-supported
+            continue-on-error: false
+            check-latest: false
             experimental: false
+          - python-version: "3.13-dev"
+            toxenv: py3
+            check-latest: true
+            experimental: true
+            continue-on-error: true
     name: unittest / ${{ matrix.toxenv }} / python ${{matrix.python-version}}
     runs-on: ubuntu-20.04
     continue-on-error: ${{ matrix.experimental }}
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           # Fetch all tags for tools/read-version
           fetch-depth: 0
       - name: Install Python ${{matrix.python-version}}
         uses: actions/setup-python@v4
         with:
           python-version: ${{matrix.python-version}}
+          check-latest: ${{matrix.check-latest}}
       - name: Install tox
         run: pip install tox
       - name: Run unittest
-        env:
-          PYTEST_ADDOPTS: -v
         run: tox -e ${{ matrix.toxenv }}