update test matrix

Author: jpstroop

.github/workflows/ci.yml

@@ -11,6 +11,9 @@ on:
 
 jobs:
   test:
+    strategy:
+      matrix:
+        python-version: ["pypy3.10", "pypy3.11", "3.10", "3.11", "3.12", "3.13"]
     name: test
     runs-on: ubuntu-latest
     steps:
@@ -19,10 +22,13 @@ jobs:
         with:
           fetch-depth: 0
 
-      - name: Set up Python 3.13
+      - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with:
-          python-version: "3.13"
+          python-version: ${{ matrix.python-version }}
+
+      - name: Display Python version
+        run: python -c "import sys; print(sys.version)"
 
       - name: Install PDM
         run: |