Bump sphinx-scylladb-theme from 1.8.3 to 1.8.4 in /docs (#418)

Bumps [sphinx-scylladb-theme](https://github.com/scylladb/sphinx-scylladb-theme) from 1.8.3 to 1.8.4.
- [Release notes](https://github.com/scylladb/sphinx-scylladb-theme/releases)
- [Commits](scylladb/sphinx-scylladb-theme@1.8.3...1.8.4)

---
updated-dependencies:
- dependency-name: sphinx-scylladb-theme
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

docs/poetry.lock

@@ -9,7 +9,7 @@ package-mode = false
 python = "^3.10"
 pygments = "^2.18.0"
 redirects_cli ="^0.1.3"
-sphinx-scylladb-theme = "^1.8.1"
+sphinx-scylladb-theme = "^1.8.4"
 sphinx-sitemap = "^2.6.0"
 sphinx-autobuild = "^2024.4.19"
 Sphinx = "^7.3.7"