`npm run docsgen` writes bad URLs in README

[kili-ilo]

The per-command GitHub file URLs that npm run docsgen generates inside /README.md are inherently flawed and will always 404.

Example:

_See code: [src/commands/collection/delete.ts](https://github.com/itopia-inc/spaces-cli/blob/v0.1.0/src/commands/collection/delete.ts)_

This is because most command files are not currently versioned.