Document `resource` attribute on `Pulumi.yaml`

[pose]

It seems we support a version attribute that could be passed to resources inside the Pulumi project YAML files. For instance, here's a snippet using pulumi-random:

name: yaml_program
runtime: yaml
description: A minimal Random Pulumi YAML program.
outputs:
  name: ${username.id}
resources:
  username:
    type: random:RandomPet
    options:
      version: 4.18.4

I checked both:

• Pulumi project YAML reference File: content/docs/iac/concepts/projects/project-file.md
• pulumi-random docs: https://www.pulumi.com/registry/packages/random/

And I couldn't find any mention of resource or version. Could we clarify where is that coming from?