🧪 Exclude PyPy jobs under macOS intel VMs

This is a follow-up for 8b8d6f8.

Ref: https://github.com/cherrypy/cheroot/pull/798/files#r2607037869

Author: webknjaz

.github/workflows/ci-cd.yml

@@ -762,7 +762,7 @@ jobs:
         # NOTE: They should be re-added once it's fixed.
         - runner-vm-os: macos-15
           python-version: pypy-3.11
-        - runner-vm-os: macos-13
+        - runner-vm-os: macos-15-intel
           python-version: pypy-3.11
 
     uses: tox-dev/workflow/.github/workflows/reusable-tox.yml@0b1e32642419392b5012b1efb66331a6babe6f79  # yamllint disable-line rule:line-length