fix(ecpool): update ecpool to 0.5.2

rebar.config

@@ -56,7 +56,7 @@
     , {ekka, {git, "https://github.com/emqx/ekka", {tag, "0.11.1"}}}
     , {gen_rpc, {git, "https://github.com/emqx/gen_rpc", {tag, "2.5.1"}}}
     , {minirest, {git, "https://github.com/emqx/minirest", {tag, "1.2.9"}}}
-    , {ecpool, {git, "https://github.com/emqx/ecpool", {tag, "0.5.1"}}}
+    , {ecpool, {git, "https://github.com/emqx/ecpool", {tag, "0.5.2"}}}
     , {replayq, "0.3.3"}
     , {pbkdf2, {git, "https://github.com/emqx/erlang-pbkdf2.git", {tag, "2.0.4"}}}
     , {emqtt, {git, "https://github.com/emqx/emqtt", {tag, "1.4.3"}}}