remove-reviewed step

This step skips documents that have already been assigned answers by the reviewer. The step follows this format:

- run-embedded: remove-reviewed

Example sr.yaml:

reviewer: mailto:user@example.com

labels:
  include:
    question: Include?
    required: true
    type: boolean

flows:
  label:
    steps:
      - uses: github:insilica/srvc-pubmed-search
        query: angry bees

      - run-embedded: remove-reviewed

      - run-embedded: label-web
        labels: [include]
        port: 5005