Update Pex 2.3.0 -> 2.30.0

[huonw]

This jumps the PEX version used to build the tools PEX forward by many versions, e.g. to have the latest and greatest pip versions available.

In the interests of one-change-at-a-time, this doesn't change that pip version.

[huonw]

The macOS arm64 crash seems to be "legitimately" caused by this upgrade, since pex-tool/pex#2427 looks very related and was released in pex 2.4.0.

It's weird, though, that symbol definitely seems like it should exist:

ProcessExecutionFailure: Process 'Find interpreter for constraints: CPython<4,>=3.7' failed with exit code 1.
stdout:

stderr:
Traceback (most recent call last):
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/runpy.py", line 193, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "/private/var/folders/4w/2glj546533jc2jfk3jgkd4740000gy/T/pants-sandbox-RyqP0p/.tmp/tmpsz5m3eke/__main__.py", line 233, in <module>
    result, should_exit, is_globals = boot(
  File "/private/var/folders/4w/2glj546533jc2jfk3jgkd4740000gy/T/pants-sandbox-RyqP0p/.tmp/tmpsz5m3eke/__main__.py", line 177, in boot
    orig_args = orig_argv()
  File "/private/var/folders/4w/2glj546533jc2jfk3jgkd4740000gy/T/pants-sandbox-RyqP0p/.tmp/tmpsz5m3eke/__main__.py", line 38, in orig_argv
    pythonapi.Py_GetArgcArgv(ctypes.byref(argc), ctypes.byref(argv))
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/ctypes/__init__.py", line 378, in __getattr__
    func = self.__getitem__(name)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/ctypes/__init__.py", line 383, in __getitem__
    func = self._FuncPtr((name_or_ordinal, self))
AttributeError: dlsym(RTLD_DEFAULT, Py_GetArgcArgv): symbol not found

Gonna take some more debugging...