Replace deprecated imp module with importlib

[hugovk]

This project uses the imp module which has been deprecated since Python 3.4 and removed in 3.12:

• Raised PendingDeprecationWarning since 3.4 (2014)
• Raised DeprecationWarning since 3.5 (2015)
• Updated DeprecationWarning to say removal in 3.12 since 3.10 (2021)
• Removal planned for 3.12 (2023)

Python 3.12 is set for release on 2023-10-02 and this library is one of the top 5,000 most-downloaded from PyPI.

Please could you upgrade to use importlib? The imp docs have suggestions on what to use to replace each function and constant.

[0-wiz-0]

This now breaks stuff like e.g. testing ninja:

===> Testing for py312-ninja-1.11.1.1
Traceback (most recent call last):
  File "/usr/pkg/bin/pytest-3.12", line 8, in <module>
    sys.exit(console_main())
             ^^^^^^^^^^^^^^
  File "/usr/pkg/lib/python3.12/site-packages/_pytest/config/__init__.py", line 206, in console_main
    code = main()
           ^^^^^^
  File "/usr/pkg/lib/python3.12/site-packages/_pytest/config/__init__.py", line 159, in main
    config = _prepareconfig(args, plugins)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/pkg/lib/python3.12/site-packages/_pytest/config/__init__.py", line 346, in _prepareconfig
    config = pluginmanager.hook.pytest_cmdline_parse(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/pkg/lib/python3.12/site-packages/pluggy/_hooks.py", line 513, in __call__
    return self._hookexec(self.name, self._hookimpls.copy(), kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/pkg/lib/python3.12/site-packages/pluggy/_manager.py", line 120, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/pkg/lib/python3.12/site-packages/pluggy/_callers.py", line 139, in _multicall
    raise exception.with_traceback(exception.__traceback__)
  File "/usr/pkg/lib/python3.12/site-packages/pluggy/_callers.py", line 122, in _multicall
    teardown.throw(exception)  # type: ignore[union-attr]
    ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/pkg/lib/python3.12/site-packages/_pytest/helpconfig.py", line 106, in pytest_cmdline_parse
    config = yield
             ^^^^^
  File "/usr/pkg/lib/python3.12/site-packages/pluggy/_callers.py", line 103, in _multicall
    res = hook_impl.function(*args)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/pkg/lib/python3.12/site-packages/_pytest/config/__init__.py", line 1152, in pytest_cmdline_parse
    self.parse(args)
  File "/usr/pkg/lib/python3.12/site-packages/_pytest/config/__init__.py", line 1501, in parse
    self._preparse(args, addopts=addopts)
  File "/usr/pkg/lib/python3.12/site-packages/_pytest/config/__init__.py", line 1388, in _preparse
    self.pluginmanager.load_setuptools_entrypoints("pytest11")
  File "/usr/pkg/lib/python3.12/site-packages/pluggy/_manager.py", line 421, in load_setuptools_entrypoints
    plugin = ep.load()
             ^^^^^^^^^
  File "/usr/pkg/lib/python3.12/importlib/metadata/__init__.py", line 205, in load
    module = import_module(match.group('module'))
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/pkg/lib/python3.12/importlib/__init__.py", line 90, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "/usr/pkg/lib/python3.12/site-packages/_pytest/assertion/rewrite.py", line 178, in exec_module
    exec(co, module.__dict__)
  File "/usr/pkg/lib/python3.12/site-packages/pytest_virtualenv.py", line 15, in <module>
    from pytest_shutil import run, cmdline
  File "/usr/pkg/lib/python3.12/site-packages/_pytest/assertion/rewrite.py", line 178, in exec_module
    exec(co, module.__dict__)
  File "/usr/pkg/lib/python3.12/site-packages/pytest_shutil/run.py", line 6, in <module>
    import imp
ModuleNotFoundError: No module named 'imp'
*** Error code 1