fix: published field in atom is duplicated

[baywet]

fixes #3582

checklist:

• Have you followed the guidelines for contributors? site is offline
• Have you checked to ensure there aren't other open pull requests on the repository for a similar change?
• Is there a corresponding ticket for your pull request?
• Have you written new tests for your changes?
• Have you successfully run the project with your changes locally? limited ruby knowledge, couldn't figure out how. help appreciated

[baywet]

gentle ping @katzj and @havocp :)