Metamodel documentation site should use latest Jinja templates

[sujaypatil96]

• This PR seeks to update the currently deployed linkml metamodel web documentation site (GitHub Pages) to use the latest Jinja templates available for use from the linkml library (docgen templates).
• It also pins the latest version of the mermaid in the mkdocs configuration because the mermaid mkdocs plugin which is supposed to pick up on a "compatible" version of mermaid does not do a very good job.
  • See: https://mkdocs-mermaid2.readthedocs.io/en/latest/#configuration
• Update multiline YAML syntax for one of the slots (extra_slots_expression) to use folded style (>-) instead of literal style (|) of block scalar syntax for reasons mentioned here: https://stackoverflow.com/questions/3790454/how-do-i-break-a-string-in-yaml-over-multiple-lines

CC: @sneakers-the-rat

[sneakers-the-rat]

Seems like we should do this for all the poetry-based repos so we don't have to keep doing manual lockfile updates like this: https://github.com/linkml/linkml/blob/main/.github/workflows/poetry-update.yaml

or else just do a pip install rather than a poetry install to always get the latest versions?

[pkalita-lbl]

@sneakers-the-rat I recently started using Dependabot's version updates feature (as opposed to its longer-standing security updates feature) in a few repositories to make periodic lock file updates. It's a lot simpler to set up than the bespoke thing we did in the linkml/linkml repo, and after using it for a few weeks it seems like it can accomplish the same thing (depending on how you configure it, of course). Here's an example PR that it produces: geneontology/gocam-py#32.

I don't think there's any particular rush in replacing what we did in linkml/linkml with the Dependabot-based setup. But if I were going to set up something new in another repo I'd probably go the Dependabot route.

[sneakers-the-rat]

Sure sure ya whatevs. I would call my action more of a hack than anything else, happy to do whatever, that looks more reliable