[boost] Adding AppVeyor as a required check to a Boost repository on Github

I am trying to add AppVeyor as a required check to the boostorg/date_time repository on Github. I have gone through the step of adding 'develop' as a protected branch, checking "Require status checks to pass before merging", and checking "Require branches to be up to date before merging". The only thing that then appears in the settings for the protected 'develop' branch is: "Status checks found in the last week for this repository" is "continuous-integration/travis-ci" "required", which is checked. Nothing about AppVeyor whatsoever. Anyone know what the Github voodoo is for getting this to happen ? I see other Boost repository with both Travis-CI and Appveyor required checks but evidently the doc for doing this for AppVeyor is non-existent in Github.