[dependabot] Update docutils requirement from <0.18 to <0.22 in /docs

Updates the requirements on [docutils](https://docutils.sourceforge.io) to permit the latest version.

---
updated-dependencies:
- dependency-name: docutils
  dependency-type: direct:production
...

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

docs/requirements.txt

@@ -2,7 +2,7 @@ Sphinx==4.5.0
 sphinx-tabs==3.3.1
 recommonmark==0.7.1
 sphinx-rtd-theme==1.1.1
-docutils<0.18
+docutils<0.22
 jinja2==3.1.4
 sphinx-copybutton==0.5.2
 # pin some older versions that are compatible with sphinx 4.5