"HTTP Error 429: Too Many Requests" for Windows and MacOS

### Description Starting last week, every CI run on Windows and MacOS platforms has been returning an HTTP 429 error. Repeated re-runs, spread one day apart, have all shown the same error. The version of cibuildwheel has been pinned to `2.23.3` for some time, for continued Python3.7 support. I also can't see any other changes that would prompt this change, compared to the [last working run](https://github.com/DiamondLightSource/pythonSoftIOC/actions/runs/22567172120/job/65365781957). Any help diagnosing this issue would be greatly appreciated. For the record, this error appears to be occurring on all platforms when attempting to get the `.pyz` file, e.g.: ``` 2026-03-16T08:26:09.0768087Z + Download https://github.com/pypa/get-virtualenv/blob/20.30.0/public/virtualenv.pyz?raw=true to C:\Users\runneradmin\AppData\Local\pypa\cibuildwheel\Cache\virtualenv-20.30.0.pyz 2026-03-16T08:26:15.3990196Z Traceback (most recent call last): 2026-03-16T08:26:15.3999869Z File "<frozen runpy>", line 198, in _run_module_as_main 2026-03-16T08:26:15.4000563Z File "<frozen runpy>", line 88, in _run_code 2026-03-16T08:26:15.4001560Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Scripts\cibuildwheel.exe\__main__.py", line 5, in <module> 2026-03-16T08:26:15.4003023Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\site-packages\cibuildwheel\__main__.py", line 49, in main 2026-03-16T08:26:15.4004252Z main_inner(global_options) 2026-03-16T08:26:15.4006343Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\site-packages\cibuildwheel\__main__.py", line 184, in main_inner 2026-03-16T08:26:15.4007383Z build_in_directory(args) 2026-03-16T08:26:15.4008402Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\site-packages\cibuildwheel\__main__.py", line 351, in build_in_directory 2026-03-16T08:26:15.4009472Z platform_module.build(options, tmp_path) 2026-03-16T08:26:15.4010429Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\site-packages\cibuildwheel\windows.py", line 394, in build 2026-03-16T08:26:15.4011377Z base_python, env = setup_python( 2026-03-16T08:26:15.4011787Z ^^^^^^^^^^^^^ 2026-03-16T08:26:15.4012767Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\site-packages\cibuildwheel\windows.py", line 273, in setup_python 2026-03-16T08:26:15.4014104Z env = virtualenv( 2026-03-16T08:26:15.4014420Z ^^^^^^^^^^^ 2026-03-16T08:26:15.4015320Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\site-packages\cibuildwheel\util.py", line 717, in virtualenv 2026-03-16T08:26:15.4016329Z virtualenv_app = _ensure_virtualenv(version) 2026-03-16T08:26:15.4016811Z ^^^^^^^^^^^^^^^^^^^^^^^^^^^ 2026-03-16T08:26:15.4017830Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\site-packages\cibuildwheel\util.py", line 644, in _ensure_virtualenv 2026-03-16T08:26:15.4018807Z download(url, path) 2026-03-16T08:26:15.4019588Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\site-packages\cibuildwheel\util.py", line 369, in download 2026-03-16T08:26:15.4020179Z with urllib.request.urlopen(url, context=context) as response: 2026-03-16T08:26:15.4020523Z ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 2026-03-16T08:26:15.4020979Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\urllib\request.py", line 215, in urlopen 2026-03-16T08:26:15.4069271Z return opener.open(url, data, timeout) 2026-03-16T08:26:15.4069890Z ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 2026-03-16T08:26:15.4070484Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\urllib\request.py", line 521, in open 2026-03-16T08:26:15.4120573Z response = meth(req, response) 2026-03-16T08:26:15.4121680Z ^^^^^^^^^^^^^^^^^^^ 2026-03-16T08:26:15.4123121Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\urllib\request.py", line 630, in http_response 2026-03-16T08:26:15.4125624Z response = self.parent.error( 2026-03-16T08:26:15.4126468Z ^^^^^^^^^^^^^^^^^^ 2026-03-16T08:26:15.4127423Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\urllib\request.py", line 559, in error 2026-03-16T08:26:15.4130044Z return self._call_chain(*args) 2026-03-16T08:26:15.4130335Z ^^^^^^^^^^^^^^^^^^^^^^^ 2026-03-16T08:26:15.4130947Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\urllib\request.py", line 492, in _call_chain 2026-03-16T08:26:15.4133535Z result = func(*args) 2026-03-16T08:26:15.4133750Z ^^^^^^^^^^^ 2026-03-16T08:26:15.4134347Z File "C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\urllib\request.py", line 639, in http_error_default 2026-03-16T08:26:15.4137112Z raise HTTPError(req.full_url, code, msg, hdrs, fp) 2026-03-16T08:26:15.4137549Z urllib.error.HTTPError: HTTP Error 429: Too Many Requests ``` ### Build log https://github.com/DiamondLightSource/pythonSoftIOC/actions/runs/23134428761/job/67194729304 ### CI config https://github.com/DiamondLightSource/pythonSoftIOC/blob/master/.github/workflows/code.yml#L106