Fix deprecation warnings

Author: jonasschmidt

config/config.exs

@@ -1,6 +1,6 @@
 # This file is responsible for configuring your application
 # and its dependencies with the aid of the Mix.Config module.
-use Mix.Config
+import Config
 
 # This configuration is loaded before any dependency and is restricted
 # to this project. If another project depends on this project, this

config/dev.exs

@@ -1 +1 @@
-use Mix.Config
+import Config

config/test.exs

@@ -1,4 +1,4 @@
-use Mix.Config
+import Config
 
 defmodule CustomFormatValidator do
   def validate(_format, _data), do: true

mix.exs

@@ -38,7 +38,7 @@ defmodule ExJsonSchema.Mixfile do
       {:ex_doc, ">= 0.0.0", only: :dev, runtime: false},
       {:excoveralls, "~> 0.14", only: :test},
       {:httpoison, "~> 1.8", only: :test},
-      {:mix_test_watch, "~> 0.7", only: [:dev, :test]},
+      {:mix_test_watch, "~> 1.2", only: [:dev, :test]},
       {:jason, "~> 1.4", only: :test},
       {:plug_cowboy, "~> 2.5", only: :test},
       {:phoenix, "~> 1.6", only: :test}