[bug] tasks.build.outputs[1]: token and environment variables are not supported

[owanio1992]

Describe the bug

I read doc token

"Tokens are variables and functions that can be used by outputs "
but output only support token function, don't support token variable

Steps to reproduce
moon.yml

fileGroups:
  storybook:
    - '.storybook/**/*'
    - 'src/**/*'
    - '**/*.stories.*'

tasks:
  build:
    inputs:
      - '@group(storybook)'     # this support 
      - '$workspaceRoot'          # this support 
    outputs:
      - '@group(storybook)'  # this support 
      - '$workspaceRoot'       # this not support

moon error msg

Error: config::parse::failed

  × Failed to parse projects/nebula-config-service/moon.yml.
  ╰─▶   × tasks.build.outputs[1]: token and environment variables are not supported

Expected behavior

outputs can use token variable

Screenshots

Environment

moon 1.28.1