chore(deps-dev): update sphinx-rtd-theme requirement

Updates the requirements on [sphinx-rtd-theme](https://github.com/readthedocs/sphinx_rtd_theme) to permit the latest version.
- [Changelog](https://github.com/readthedocs/sphinx_rtd_theme/blob/master/docs/changelog.rst)
- [Commits](readthedocs/sphinx_rtd_theme@1.2.0...2.0.0)

---
updated-dependencies:
- dependency-name: sphinx-rtd-theme
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

pyproject.toml

@@ -62,7 +62,7 @@ pytest-benchmark = "*"
 
 [tool.poetry.group.docs.dependencies]
 myst-nb = "^0.17.0"
-sphinx-rtd-theme = "^1.2.0"
+sphinx-rtd-theme = ">=1.2,<3.0"
 sphinx-autodoc-typehints = "^1.23.0"
 sphinx-autodocgen = "^1.3"
 jupytext = "^1.14.5"
@@ -82,7 +82,7 @@ pandas-stubs = "<3"
 
 [tool.poetry.group.notebooks.dependencies]
 myst-nb = "^0.17.0"
-sphinx-rtd-theme = "^1.2.0"
+sphinx-rtd-theme = ">=1.2,<3.0"
 sphinx-autodoc-typehints = "^1.23.0"
 sphinx-autodocgen = "^1.3"
 jupytext = "^1.14.5"