Test on multiple versions of Python.

.github/workflows/tests.yml

@@ -6,13 +6,22 @@ jobs:
   test:
     runs-on: ubuntu-latest
 
+    strategy:
+      fail-fast: false
+      matrix:
+        python: ['3.10', 3.11, 3.12, pypy-3.10]
+
     steps:
-    - uses: actions/checkout@v3
-    - run: python3 util/install_deps.py
+    - uses: actions/checkout@v4
+    - uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python }}
+    - run: pip install
+        pip==24.0 setuptools==69.1.1 wheel==0.42.0 pytest==8.0.2
+    - run: python util/install_deps.py
     - run: pip install .
-    - uses: actions/cache@v3
+    - uses: actions/cache@v4
       with:
         key: cache-dir
         path: /home/runner/.cache/simalq
-    - run: pip install pytest
     - run: pytest tests