Update mermaid to 10.8.0

[kmoschcau]

The version used by this plugin is over half a year old and is missing features that are shown on the mermaid page.

I just replaced the bundled mermaid version of the plugin with a 10.8.0 version fetched from npm and it works without problems so far.

This is going to fix #627 and #519.

[sh-cau]

I second this and would even like to have mermaid > 10.9.0 (to use until in gantt charts)