Use YamlElixir 2.0 (#42)

YamlElixir 2.0 is functionally identical to 1.3, except for the breaking API
change which was initially introduced in 1.4. Updating the version constraint to
2.0 allows us to remove the 1.3/1.4 negotiation hack.

lib/kazan/server.ex

@@ -34,19 +34,7 @@ defmodule Kazan.Server do
   """
   @spec from_kubeconfig(String.t(), Keyword.t()) :: t
   def from_kubeconfig(config_file, options \\ []) do
-    # YamlElixir made a breaking change in a minor version, so we need to make
-    # sure we call the appropriate function for the version installed.
-    # Can hopefully get rid of this at some point.
-    Code.ensure_loaded(YamlElixir)
-
-    func =
-      if Kernel.function_exported?(YamlElixir, :read_from_file!, 1) do
-        :read_from_file!
-      else
-        :read_from_file
-      end
-
-    data = apply(YamlElixir, func, [config_file])
+    data = YamlElixir.read_from_file!(config_file)
 
     basepath = config_file |> Path.absname() |> Path.dirname()
 

mix.exs

@@ -41,7 +41,7 @@ defmodule Kazan.Mixfile do
   defp deps do
     [{:poison, "~> 2.0 or ~> 3.0"},
      {:httpoison, "~> 0.10 or ~> 1.0"},
-     {:yaml_elixir, "~> 1.3"},
+     {:yaml_elixir, "~> 2.0"},
 
      # Dev dependencies
      {:ex_doc, "~> 0.14", only: :dev},