分布式任务系统，使用etcd做分布式锁。
go crontab
go mod edit -replace github.com/coreos/bbolt@v1.3.4=go.etcd.io/bbolt@v1.3.4
go mod edit -replace google.golang.org/grpc@v1.29.1=google.golang.org/grpc@v1.26.0
go mod tidy
go mod github.com/coreos/etcd/clientv3
#old mongo driver is failured
go get github.com/mongodb/mongo-go-driver@v0.0.17