chore: pin gun to 1.3.7

mix.exs

@@ -73,7 +73,7 @@ defmodule EMQXUmbrella.MixProject do
       {:esasl, github: "emqx/esasl", tag: "0.2.0"},
       {:jose, github: "potatosalad/erlang-jose", tag: "1.11.2"},
       # in conflict by ehttpc and emqtt
-      {:gun, github: "emqx/gun", tag: "1.3.6", override: true},
+      {:gun, github: "emqx/gun", tag: "1.3.7", override: true},
       # in conflict by emqx_connectior and system_monitor
       {:epgsql, github: "emqx/epgsql", tag: "4.7-emqx.2", override: true},
       # in conflict by mongodb and eredis_cluster

rebar.config

@@ -48,6 +48,7 @@
     , {redbug, "2.0.7"}
     , {gpb, "4.11.2"} %% gpb only used to build, but not for release, pin it here to avoid fetching a wrong version due to rebar plugins scattered in all the deps
     , {typerefl, {git, "https://github.com/ieQu1/typerefl", {tag, "0.9.1"}}}
+    , {gun, {git, "https://github.com/emqx/gun", {tag, "1.3.7"}}}
     , {ehttpc, {git, "https://github.com/emqx/ehttpc", {tag, "0.2.0"}}}
     , {gproc, {git, "https://github.com/uwiger/gproc", {tag, "0.8.0"}}}
     , {jiffy, {git, "https://github.com/emqx/jiffy", {tag, "1.0.5"}}}