Update sphinx-rtd-theme requirement from 1.2.1 to 1.2.2 (#260)

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@1.2.1...1.2.2)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

pyproject.toml

@@ -45,5 +45,5 @@ sphinx = "6.2.1"
 sphinx-argparse = "0.4.0"
 sphinx-copybutton = "0.5.2"
 sphinx-pydantic = "0.1.1"
-sphinx-rtd-theme = "1.2.1"
+sphinx-rtd-theme = "1.2.2"
 sphinx-jsonschema = "1.15"