build(deps): Bump sphinx-rtd-theme from 3.0.0rc3 to 3.0.0rc4

Bumps [sphinx-rtd-theme](https://github.com/readthedocs/sphinx_rtd_theme) from 3.0.0rc3 to 3.0.0rc4.
- [Changelog](https://github.com/readthedocs/sphinx_rtd_theme/blob/master/docs/changelog.rst)
- [Commits](readthedocs/sphinx_rtd_theme@3.0.0rc3...3.0.0rc4)

---
updated-dependencies:
- dependency-name: sphinx-rtd-theme
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements-docs.txt

@@ -3,4 +3,4 @@ recommonmark==0.7.1
 Sphinx==8.0.2
 sphinx-autodoc2==0.5.0
 myst-parser==4.0.0
-sphinx-rtd-theme==3.0.0rc3
+sphinx-rtd-theme==3.0.0rc4