docs: fix root sitemap.xml in multiversion builds

[dgarcia360]

Problem

https://java-driver.docs.scylladb.com/sitemap.xml returns 404, while the per-version https://java-driver.docs.scylladb.com/stable/sitemap.xml exists.

Solution

Bump sphinx-scylladb-theme to 1.9.3. The theme copies the stable version's sitemap.xml to the site root during multiversion builds since 1.9.3; the lockfile was at 1.9.2.

How to test

Run make multiversion and check sitemap.xml is generated at the root of _build/dirhtml.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Run ID: 55e33476-9954-415d-a988-425d1456f610

📥 Commits

Reviewing files that changed from the base of the PR and between 088290a and 0e1fb16.

⛔ Files ignored due to path filters (1)

• docs/uv.lock is excluded by !**/*.lock

📒 Files selected for processing (1)

• docs/pyproject.toml

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📝 Walkthrough

Walkthrough

The documentation project updates its sphinx-scylladb-theme build dependency from version 1.9.2 to 1.9.3. No other dependencies or configuration declarations change.

Possibly related PRs

• scylladb/java-driver#932: Updates the same documentation theme dependency in docs/pyproject.toml.
• scylladb/java-driver#977: Updates the same dependency from version 1.9.2 to 1.9.3.

Suggested reviewers: dkropachev

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly matches the main change: fixing the root sitemap.xml behavior in multiversion docs builds.
Description check	✅ Passed	The description accurately describes the version bump and the sitemap.xml fix, which matches the changeset.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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_{Comment @coderabbitai help to get the list of available commands.}

[dgarcia360]

Not necessary, fixed by #977