Run tests on macos too.

.github/workflows/testing.yml

@@ -21,8 +21,9 @@ jobs:
       max-parallel: 20
       matrix:
         python-version: ["3.10"]
+        os: [ "ubuntu-latest", "macos-latest" ]
 
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.config.os }}
     env:
       PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION: "python"
       PMG_MAPI_KEY: ${{ secrets.PMG_MAPI_KEY }}
@@ -35,7 +36,7 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
           cache: pip
-          cache-dependency-path: '**/requirements.txt'
+          cache-dependency-path: '**/pyproject.toml'
       - name: Install dependencies
         run: |
           pip install -e '.[ci]'