Make httpoison dependency >= 1.8.0

mix.exs

@@ -31,7 +31,7 @@ defmodule Ibanity.MixProject do
   # Run "mix help deps" to learn about dependencies.
   defp deps do
     [
-      {:httpoison, ">= 1.8.2"},
+      {:httpoison, ">= 1.8.0"},
       {:jason, "~> 1.3"},
       {:recase, "~> 0.7"},
       {:ex_crypto, "~> 0.9.0"},