Updating Docusaurus version from 3.7 to 3.8 (#2457)

## Motivation for the change, related issues

This pull request updates the Docusaurus version from 3.7 to 3.8.1.
Version 3.8 includes performance improvements and experimental features
designed to facilitate the transition to version 4.0.

To know more about version 3.8, check the [Docusaurus
documentation](https://docusaurus.io/blog/releases/3.8).

This version doesn't contain known breaking changes.

Author: fellyph