Incompatibility with Sphinx >=9.0: Config.read() TypeError during build

[kimbyungnam]

Current Behavior

When using sphinx-multiversion with Sphinx >= 9.0, documentation builds fail with a TypeError related to Config.read().

This appears to be caused by a breaking change in Sphinx's internal config loading API, which sphinx-multiversion relies on.

sphinx-doc/sphinx#13633

The build fails with the following error:

TypeError: Config.read() takes 2 positional arguments but 3 were given

Full traceback (excerpt):

  File "../site-packages/sphinx_multiversion/main.py", line 182, in main
    config = load_sphinx_config(
             ^^^^^^^^^^^^^^^^^^^
  File "../site-packages/sphinx_multiversion/main.py", line 88, in load_sphinx_config
    raise result
TypeError: Config.read() takes 2 positional arguments but 3 were given

Expected Behavior

Reproduction Steps

1. Install dependencies:

   pip install sphinx>=9 sphinx-multiversion

2. Run sphinx-multiversion:

   sphinx-multiversion docs/source docs/build

3. See error

   TypeError: Config.read() takes 2 positional arguments but 3 were given

Environment

• OS: Windows11
• Python: 3.11, 3.12

Additional Context