debug: make sure PyPy 3.9 is not available on mac0S

Author: DimitriPapadopoulos

.github/workflows/ci.yml

@@ -72,7 +72,7 @@ jobs:
           - python-version: "3.9"
             runs-on: ubuntu-latest
             cmake-version: "3.20.x"
-          - python-version: "pypy-3.10"
+          - python-version: "pypy-3.9"
             runs-on: macos-latest
             cmake-version: "3.15.x"
           - python-version: "3.9"