Emitted schemas do not honor catalog

[JohannesRudolph]

I'm running this tap via meltano. I'm hitting the same bug as #130, so I was thinking I could work around this by providing a custom catalog to the tap, via meltano.yml

    select:
      - issues.id
      - issues.url
      - issues.repository_url
      - issues.state
      - issues.title
      - issues.number
      - issues.comments
      - issues.closed_at

The singer record messages emitted by the tap only include the right fields. However, it appears the schema message does not honor the catalog and still includes the problematic issues.assignee field. This means I'm not able to connect tap-github to target-bigquery due to the missing issue.assignee schema (even though this property is not selected!)

I'm new to the singer ecosystem, so I have checked other taps and they seem to adapt the schema message they emit based on the catalog provided to the tap. But I may be getting this wrong, so I appreciate your feedback if this is a problem with this tap or if I need to look elsewhere.