QoS of PUBREL packet should be 1 about emqx

[emqplus]

--- a/apps/emqtt/src/emqtt_protocol.erl
+++ b/apps/emqtt/src/emqtt_protocol.erl
@@ -230,9 +230,14 @@ make_packet(Type) when Type >= ?CONNECT andalso Type =< ?DISCONNECT ->
#mqtt_packet{ header = #mqtt_packet_header { type = Type } }.

make_packet(PubAck, PacketId) when PubAck >= ?PUBACK andalso PubAck =< ?PUBCOMP ->

• #mqtt_packet { header = #mqtt_packet_header { type = PubAck},
• #mqtt_packet { header = #mqtt_packet_header { type = PubAck, qos = puback_qos(PubAck) },
  variable = #mqtt_packet_puback { packet_id = PacketId}}.

+puback_qos(?PUBACK) -> ?QOS_0;
+puback_qos(?PUBREC) -> ?QOS_0;
+puback_qos(?PUBREL) -> ?QOS_1;
+puback_qos(?PUBCOMP) -> ?QOS_0;