I use the below custom label to get it to work, it works pretty well

druvainsync)
name="Druva inSync"
type="pkgInDmg"
appNewVersion=$(getJSONValue "$(curl -fsL curl -fs https://downloads.druva.com/insync/js/data.json)" "[1].supportedVersions[0]")
downloadURL=$(getJSONValue "$(curl -fsL curl -fs https://downloads.druva.com/insync/js/data.json)" "[1].installerDetails[0].downloadURL")
expectedTeamID="JN6HK3RMAP"
;;