[deno] add --unstable-workspaces support

[miguelrk]

A barebones workspaces feature has landed in deno.json to allow composing import maps. These could be leveraged in the monorepo setup. See denoland/deno#20410 for details.

// deno.json
{
  "workspaces": [
     "a",
     "b"
  },
  "imports": {
    "express": "npm:express@5"
   }
}

// a/deno.json
{
  "name": "a",
  "version": "1.0.2",
  "imports": {
    "kleur": "npm:kleur"
  }
}

// b/deno.json
{
  "name": "b",
  "version": "0.51.0",
  "imports": {
    "chalk": "npm:chalk"
  }
}

See issue and response from thread

Workspaces are currently not supported, you can use deno.disablePaths settings to ignore certain directories

[miguelrk]

@deer this could be relevant for the following CI/CD and types improvement issues:

• [types] fix all TypeScript errors #88
• [cli] more CLI tests #96
• [ci/cd] better release workflow #97