Bump docutils from 0.19 to 0.21.1

Bumps [docutils](https://docutils.sourceforge.io) from 0.19 to 0.21.1.

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

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

pyproject.toml

@@ -32,7 +32,7 @@ dependencies = [
 
 [project.optional-dependencies]
 dev = [
-    "docutils==0.19",
+    "docutils==0.21.1",
     "mistune==2.0.4",
 
     "attribution==1.6.2",