removed confusing sla: config from examples/schedule.yml
removed confusing sla: config from examples/schedule.yml

KimuraTakaumi/digdag,treasure-data/digdag,KimuraTakaumi/digdag,KimuraTakaumi/digdag,treasure-data/digdag,KimuraTakaumi/digdag,treasure-data/digdag,KimuraTakaumi/digdag,treasure-data/digdag,treasure-data/digdag,treasure-data/digdag,KimuraTakaumi/digdag,treasure-data/digdag