Bump docutils from 0.20.1 to 0.21.2 in /requirements (#2312)

Bumps [docutils](https://docutils.sourceforge.io) from 0.20.1 to 0.21.2.

---
updated-dependencies:
- dependency-name: docutils
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements/docs-requirements.txt

@@ -2,4 +2,4 @@ sphinx_rtd_theme==2.0.0
 sphinxcontrib-openapi==0.8.3
 sphinxcontrib-redoc==1.6.0
 recommonmark==0.7.1
-docutils==0.20.1
+docutils==0.21.2