disable pypy builds

they build OK but result in errors like the following when you try to import the lcm module:

      import lcm
  ../venv-test-arm64/lib/pypy3.8/site-packages/lcm/__init__.py:23: in <module>
      from lcm import _lcm
  E   ImportError: cannot import name '_lcm' from partially initialized module 'lcm' (most likely due to a circular import)

.github/workflows/build_wheels.yml

@@ -12,8 +12,7 @@ jobs:
         # macos-13 is an intel runner, macos-14 is apple silicon
         os: [ubuntu-latest, macos-13, macos-14]
         arch: [auto, aarch64]
-        python: [cp37-*, cp38-*, cp39-*, cp310-*, cp311-*, cp312-*,
-                 pp37-*, pp38-*, pp39-*, pp310-*]
+        python: [cp37-*, cp38-*, cp39-*, cp310-*, cp311-*, cp312-*]
         include:
           - os: macos-13
             macos_deployment_target: 13
@@ -30,8 +29,6 @@ jobs:
             arch: aarch64
           - os: macos-14
             python: cp37-*
-          - os: macos-14
-            python: pp37-*
 
     steps:
       - uses: actions/checkout@v4