Enable testing with Sphinx 7.2+ (also on Python 3.12)

[befeleme]

I can't use patch from #27 in Fedora, because we already build packages with Python 3.12, and the internals of pathlib.Path were rewritten. See traceback below.

I tried to understand what is the desired outcome of the tests here and since Sphinx is heading towards the standard Path objects, there's no need to monkeypatch the attributes anymore: the Path.resolve() method does the relevant work for us.
Also, adding tests with Python 3.12 since it's already out.

_________________________________________ test_jquery_installed_sphinx_ge_60 __________________________________________

blank_app = <function blank_app.<locals>.inner at 0x7f2ef84f7560>

    @pytest.mark.skipif(sphinx.version_info[:2] < (6, 0),
                        reason="Requires Sphinx 6.0 or greater")
    def test_jquery_installed_sphinx_ge_60(blank_app):
>       out_dir = blank_app(confoverrides={"extensions": ["sphinxcontrib.jquery"]})

tests/test_jquery_installed.py:67: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
tests/test_jquery_installed.py:38: in inner
    return run_blank_app(Path(tmpdir), **kwargs)
tests/test_jquery_installed.py:19: in run_blank_app
    app = SphinxTestApp(**kwargs, srcdir=srcdir)
../venv213/lib64/python3.12/site-packages/sphinx/testing/util.py:120: in __init__
    super().__init__(srcdir, confdir, outdir, doctreedir,
../venv213/lib64/python3.12/site-packages/sphinx/application.py:152: in __init__
    self.srcdir = _StrPath(srcdir).resolve()
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = FakePath('/tmp/pytest-of-ksurma/pytest-4/test_jquery_installed_sphinx_g1'), args = (), kwargs = {}

    def resolve(self, *args, **kwargs):
>       return self._path
E       AttributeError: 'FakePath' object has no attribute '_path'. Did you mean: '_hash'?

[befeleme]

Ok, compatibility is an issue -switching to draft.