Simple fix for issue #420 (#421)

Supplement missing default configuration

Co-authored-by: 无别 <62596032+Tiper-In-Github@users.noreply.github.com>

Author: wubie052

pkg/config/viper_config.go

@@ -88,6 +88,8 @@ func (c *Config) fillDefaultValues() {
 		"pitaya.cluster.rpc.server.nats.buffer.push":            pitayaConfig.Cluster.RPC.Server.Nats.Buffer.Push,
 		"pitaya.cluster.sd.etcd.dialtimeout":                    pitayaConfig.Cluster.SD.Etcd.DialTimeout,
 		"pitaya.cluster.sd.etcd.endpoints":                      pitayaConfig.Cluster.SD.Etcd.Endpoints,
+		"pitaya.cluster.sd.etcd.user":                           pitayaConfig.Cluster.SD.Etcd.User,
+		"pitaya.cluster.sd.etcd.pass":                           pitayaConfig.Cluster.SD.Etcd.Pass,
 		"pitaya.cluster.sd.etcd.prefix":                         pitayaConfig.Cluster.SD.Etcd.Prefix,
 		"pitaya.cluster.sd.etcd.grantlease.maxretries":          pitayaConfig.Cluster.SD.Etcd.GrantLease.MaxRetries,
 		"pitaya.cluster.sd.etcd.grantlease.retryinterval":       pitayaConfig.Cluster.SD.Etcd.GrantLease.RetryInterval,