adds version number to config and dynamic accept-header (altyaper#8)

Author: kdaker

config/config.exs

@@ -3,4 +3,5 @@ use Mix.Config
 config :conekta,
   publickey: "PUBLIC",
   privatekey: "PRIVATE",
-  locale: "es"
+  locale: "es",
+  apiversion: "2.0.0"

lib/wrapper.ex

@@ -1,7 +1,7 @@
 defmodule Conekta.Wrapper do
     @moduledoc false
     use HTTPoison.Base
-    @conekta_accept_header "application/vnd.conekta-v2.0.0+json"
+    @conekta_accept_header "application/vnd.conekta-v{{version}}+json"
 
     def process_url(url) do
         "https://api.conekta.io/" <> url
@@ -13,7 +13,11 @@ defmodule Conekta.Wrapper do
 
     def headers do
         basic_auth = "Basic " <> Base.encode64(key() <> ":")
-        ["Accept": @conekta_accept_header, "Accept-Language": locale(),"Content-type": "application/json", "Authorization": basic_auth]
+        ["Accept": accept_header(), "Accept-Language": locale(),"Content-type": "application/json", "Authorization": basic_auth]
+    end
+
+    def accept_header do
+        String.replace(@conekta_accept_header, "{{version}}", api_version())
     end
 
     def key do
@@ -24,4 +28,7 @@ defmodule Conekta.Wrapper do
         Application.get_env(:conekta, :locale)
     end
 
+    def api_version do
+        Application.get_env(:conekta, :apiversion)
+    end
 end