fix broker type yaml tag

config/config.go

@@ -37,7 +37,7 @@ type ServerConfig struct {
 	APIHost               string `yaml:"apihost"`
 	APIPort               string `yaml:"apiport"`
 	MQHOST                string `yaml:"mqhost"`
-	BrokerType            string `yaml:"brokertype`
+	BrokerType            string `yaml:"brokertype"`
 	EmqxRestEndpoint      string `yaml:"emqxrestendpoint"`
 	MasterKey             string `yaml:"masterkey"`
 	DNSKey                string `yaml:"dnskey"`