Feature Request: Include supported version of Mermaid in documentation

[TonyBrookILSTU]

I'd like to request a small note on the VS Code "Details" page that indicates what version of Mermaid is currently supported by this plugin.

When I visited the Mermaid homepage today to check some syntax, I found support for a couple of new experimental diagram types. These diagram types (mindmap and sankey) are not currently supported by this plugin. So I wanted to see what might be, and found the details panel lacking.

My suggestion would be to add it to the Readme.md on line 3

Something like:

Syntax support for the Mermaid charting language. Full support for Release 10.2.1. Partial support for Release 10.2.4 - currently in development

Syntax support for the [Mermaid charting language](https://github.com/knsv/mermaid). Full support for [Release 10.2.1](https://github.com/mermaid-js/mermaid/releases/tag/v10.2.1). Partial support for [Release 10.2.4](https://github.com/mermaid-js/mermaid/releases/tag/v10.2.4) - currently in development

Or, alternatively, a badge would accomplish something similar:

The important part is just letting folks know what Mermaid features they can expect code highlighting with.

[bpruitt-goddard]

Unfortunately, the mermaid language moves a lot faster that my time commitments allow to maintain this package and this repo tends to fall behind. Previously, there was an area in the readme that included which diagrams were supported - maybe that should be brought back and placed near the top to make it clear? Something like (not accurate, just an example for formatting):

## Supported Diagrams
- [x] Sequence Diagram
- [x] State Diagram
- [ ] Mind Map
- [ ] Quadrant Chart