Group is no longer configured via configuration.yaml so that’s prob your issue. It’s gone a while though (since 0.107) so strange you’re only seeing this now 
You can configure Groups via UI using Helpers or using group platform in yaml for lights, switches, etc
EDIT: seems I’m wide of the mark and incorrect here in case anyone else reading this…groups can still be configured via yaml, it’s just not recommended…thanks to the community (see below) for correcting me, especially those who did so constructively 