Package check result: NOTE

Check: CRAN incoming feasibility, Result: NOTE
  Maintainer: ‘Liam Hobby <liam.f.hobby@gsk.com>’
  
  Found the following (possibly) invalid URLs:
    URL: https://RValidationHub.slack.com
      From: README.md
      Status: 404
      Message: Not Found

No changes to worse in reverse depends.