Fix docutils version

[forsyth2]

Summary

Objectives:

• Resolve issue seen https://github.com/E3SM-Project/zstash/actions/runs/18233515307/job/51922401478

Issue resolution:

• Follow-up to Update Python support #384.

Select one: This pull request is...

• a bug fix: increment the patch version
• a small improvement: increment the minor version
• a new feature: increment the minor version
• an incompatible (non-backwards compatible) API change: increment the major version

Small Change

• To merge, I will use "Squash and merge". That is, this change should be a single commit.
• Logic: I have visually inspected the entire pull request myself.
• Pre-commit checks: All the pre-commits checks have passed.

[forsyth2]

@xylar Following up from #384 (comment).

Is there a way to test this before merging??

Also, I don't even see docutils in the .github/workflows/build_workflow.yml to update it there.

[forsyth2]

Never mind, I missed #386. Closing this.