Update Docusaurus framework

[RoiArthurB]

Is your request related to a problem? Please describe.
Even tho nothing is wrong nor now nor later (to some extends), the website is running on the fixed version 3.6.1 at the moment. This fixed version prevents using the evolution of the Docusaurus' development (fixing bugs, being lighter to browse, fix issues with some browser, else) as with the 3.8.0 released today.

As far as I remember, the issue was mainly caused by some Markdown stricter rules that I didn't have time to manage; but it's safe to assume that it can be done (or those rules have been updated since).

Describe the solution you'd like
Run the website on the latest version