Cirrus CI: trying install_pre_requirements_script as key.

Author: unhyperbolic

.cirrus.yml

@@ -18,7 +18,7 @@ cirrus_wheels_macos_arm64_task:
       pip install git+https://github.com/3-manifolds/snappy_manifolds &&
       pip install git+https://github.com/3-manifolds/Spherogram
     CIBW_TEST_COMMAND: python -m snappy.test --skip-modern-opengl
-  install_pre_requirements:
+  install_pre_requirements_script:
     - brew install python3 pipx
     - python3 --version
   run_cibuildwheel_script: