Update unit test matrix

Author: cgoldberg

.github/workflows/ci-python.yml

@@ -80,12 +80,19 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: ubuntu
-          - os: macos
+          - python-version: '3.10'
+            os: ubuntu
+          - python-version: '3.10'
+            os: macos
+          - python-version: '3.13'
+            os: ubuntu
+          - python-version: '3.13'
+            os: macos
     with:
-      name: Unit Tests (${{ matrix.os }})
+      name: Unit Tests (${{ matrix.python-version }}, ${{ matrix.os }})
       os: ${{ matrix.os }}
-      cache-key: python-unit-test-${{ matrix.os }}
+      python-version: ${{ matrix.python-version }}
+      cache-key: python-unit-test-${{ matrix.python-version }}
       run: |
         bazel test //py:unit