Update poison version

Author: clarkema

mix.exs

@@ -30,7 +30,7 @@ defmodule ElixirNsq.Mixfile do
   # Type "mix help deps" for more examples and options
   defp deps do
     [
-      {:poison, "~> 1.5.0"},
+      {:poison, "~> 3.1.0"},
       {:ibrowse, "~> 4.2"},
       {:httpotion, "~> 2.1.0"},
       {:uuid, "~> 1.1.2"},

mix.lock

@@ -4,7 +4,7 @@
   "http_server": {:git, "https://github.com/parroty/http_server.git", "922d10420836a51289ed04f0bb5022bf695da1ab", []},
   "httpotion": {:hex, :httpotion, "2.1.0", "3fe84fbd13d4560c2514da656d022b1191a079178ee4992d245fc3c33c01ee18", [:mix], []},
   "ibrowse": {:hex, :ibrowse, "4.4.0", "2d923325efe0d2cb09b9c6a047b2835a5eda69d8a47ed6ff8bc03628b764e991", [:rebar3], []},
-  "poison": {:hex, :poison, "1.5.0", "f2f4f460623a6f154683abae34352525e1d918380267cdbd949a07ba57503248", [:mix], []},
+  "poison": {:hex, :poison, "3.1.0", "d9eb636610e096f86f25d9a46f35a9facac35609a7591b3be3326e99a0484665", [:mix], []},
   "ranch": {:hex, :ranch, "1.2.0", "b286a948a0706a700a9f577e5cecbb2dc66097ea79f3ddb20ba5536069bdb7aa", [:make], []},
   "secure_random": {:hex, :secure_random, "0.2.0", "d5458ab5613410439c21a2fdbc52e98e6c96338f3ea25d08220c30cfc55f1238", [:mix], []},
   "socket": {:hex, :socket, "0.3.7", "68c029a8449fc6efc5f4c3bdf6d8b19ca94d3304e419f364c5cfc8b716f7c219", [:mix], []},