test: run functional tests with different Python versions

.github/workflows/functional_tests.yml

@@ -9,13 +9,21 @@ on:
 
 jobs:
   functional_tests:
+    name: Functional tests for Python ${{ matrix.python-version }}
     runs-on: "ubuntu-latest"
     environment: test
+
+    strategy:
+      fail-fast: false
+      max-parallel: 1
+      matrix:
+        python-version: [ "3.9", "3.10", "3.11", "3.12", "pypy3.9", "pypy3.12" ]
+
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
         with:
-          python-version: "3.12"
+          python-version: ${{ matrix.python-version }}
       - name: "Install dependencies"
         run: |
           python -m pip install --upgrade pip