ci: use a matrix array instead of includes

Author: dcermak

.github/workflows/default.yml

@@ -31,12 +31,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        include:
-          - python_version: "3.8"
-          - python_version: "3.9"
-          - python_version: "3.10"
-          - python_version: "3.11"
-          - python_version: "3.12"
+        python_version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
     steps:
       - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python_version }}