Fix json

[aelsabbahy]

Checklist

• [ ] make test-all (UNIX) passes. CI will also test this
• [ ] unit and/or integration tests are included (if applicable)
• [ ] documentation is changed or added (if applicable)

Description of change

Fixes bug in #840

This was a regression from goss 3 -> 4

# file: goss.yaml
command:
  Always-succeeds:
    exec: /bin/true
    exit-status: 0
  Always-fails:
    exec: /bin/false
    exit-status: 0

$ goss.3.18 v -f json | jq '.results[]| {"resource-id", successful}' -c|sort
{"resource-id":"Always-fails","successful":false}
{"resource-id":"Always-succeeds","successful":true}

$ goss v -f json | jq '.results[]| {"resource-id", successful}' -c|sort
{"resource-id":"Always-fails","successful":false}
{"resource-id":"Always-succeeds","successful":true}

Note: SKIPPED is considered success, this matches goss 3.x behavior