Bump sphinx-rtd-theme from 1.0.0 to 1.2.0

Bumps [sphinx-rtd-theme](https://github.com/readthedocs/sphinx_rtd_theme) from 1.0.0 to 1.2.0.
- [Release notes](https://github.com/readthedocs/sphinx_rtd_theme/releases)
- [Changelog](https://github.com/readthedocs/sphinx_rtd_theme/blob/master/docs/changelog.rst)
- [Commits](readthedocs/sphinx_rtd_theme@1.0.0...1.2.0)

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

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

requirements.txt

@@ -9,6 +9,6 @@ pytest-runner==5.3.1
 pytest-asyncio==0.15.1
 coveralls==3.3.1
 pycodestyle==2.9.1
-sphinx-rtd-theme==1.0.0
+sphinx-rtd-theme==1.2.0
 sphinx==5.3.0
 mypy==0.942