Update mermaid to v10.9.1

[AlixANNERAUD]

Hello, would it be possible to update Mermaid to version v10.9.1? The introduction of the "block diagram" feature in version v10.8.0 would be very useful with nbconvert. Additionally, would it be possible to manually specify the Mermaid version in the configuration file if needed (for example: c.SlidesExporter.font_awesome_url, c.SlidesExporter.mermaid_js_url doesn't work) Thank you for this great project.