Bump docutils from 0.18.1 to 0.20.1 in /requirements (#20712)

Bumps [docutils](https://docutils.sourceforge.io/) from 0.18.1 to 0.20.1.

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

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

requirements/docs.txt

@@ -21,9 +21,9 @@ Babel==2.14.0 \
     --hash=sha256:6919867db036398ba21eb5c7a0f6b28ab8cbc3ae7a73a44ebe34ae74a4e7d363 \
     --hash=sha256:efb1a25b7118e67ce3a259bed20545c29cb68be8ad2c784c83689981b7a57287
 # docutils is required by Sphinx
-docutils==0.18.1 \
-    --hash=sha256:23010f129180089fbcd3bc08cfefccb3b890b0050e1ca00c867036e9d161b98c \
-    --hash=sha256:679987caf361a7539d76e584cbeddc311e3aee937877c87346f31debc63e9d0
+docutils==0.20.1 \
+    --hash=sha256:96f387a2c5562db4476f09f13bbab2192e764cac08ebbf3a34a95d9b1e4a59d6 \
+    --hash=sha256:f08a4e276c3a1583a86dce3e34aba3fe04d02bba2dd51ed16106244e8a923e3b
 # imagesize is required by Sphinx
 imagesize==1.4.1 \
     --hash=sha256:0d8d18d08f840c19d0ee7ca1fd82490fdc3729b7ac93f49870406ddde8ef8d8b \