Bump sphinx-rtd-theme from 1.2.0 to 1.2.2

Bumps [sphinx-rtd-theme](https://github.com/readthedocs/sphinx_rtd_theme) from 1.2.0 to 1.2.2.
- [Changelog](https://github.com/readthedocs/sphinx_rtd_theme/blob/master/docs/changelog.rst)
- [Commits](readthedocs/sphinx_rtd_theme@1.2.0...1.2.2)

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

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

requirements/requirements-test.lock.txt

@@ -237,7 +237,7 @@ sphinx-autobuild==2021.3.14
     # via -r requirements/requirements-test.in
 sphinx-jinja==2.0.2
     # via -r requirements/requirements-test.in
-sphinx-rtd-theme==1.2.1
+sphinx-rtd-theme==1.2.2
     # via -r requirements/requirements-test.in
 sphinxcontrib-applehelp==1.0.4
     # via sphinx