Add support for sequence diagrams

This upgrades the mermaid.js library to v10.8.0 to support more recently adopted diagram types.

This seemed to work locally with sequence, timeline and C4 diagrams but I haven’t tested extensively.

_layouts/reveal.html

@@ -126,7 +126,7 @@
 					{ src: '{{ site.reveal_path }}plugin/highlight/highlight.js', async: true, callback: function() { hljs.initHighlightingOnLoad(); } },
 					{ src: '{{ site.reveal_path }}plugin/zoom-js/zoom.js', async: true, condition: function() { return !!document.body.classList; } },
 					{% if site.mermaid_diagrams %}
-					{ src: 'https://cdn.jsdelivr.net/npm/mermaid@9.1.6/dist/mermaid.min.js'},
+					{ src: 'https://cdn.jsdelivr.net/npm/mermaid@10.8.0/dist/mermaid.min.js'},
 					{ src: '{{ 'assets/js/mermaid/reveal-js-mermaid-plugin.js' | relative_url }}'},
 					{% endif %}
 					{% if site.reveal_notes_server %}