update Travis CI configuration

.travis.yml

@@ -1,27 +1,6 @@
 language: elixir
-elixir:
+elixir: 1.6.1
-  - 1.3.4
+otp_release: 20.3
-  - 1.4.5
-  - 1.5.2
-otp_release:
-  - 20.1
-  - 19.3
-  - 18.3
-matrix:
-  # newest/oldest pair
-  exclude:
-    - elixir: 1.5.2
-      otp_release: 19.3
-    - elixir: 1.5.2
-      otp_release: 18.3
-    - elixir: 1.4.5
-      otp_release: 20.1
-    - elixir: 1.4.5
-      otp_release: 18.3
-    - elixir: 1.3.4
-      otp_release: 20.1
-    - elixir: 1.3.4
-      otp_release: 19.3
 sudo: false
 notifications:
   recipients:
@@ -29,7 +8,8 @@ notifications:
 env:
   - MIX_ENV=test
 script:
-  - "mix do local.hex --force, deps.get, test"
+  - mix format --check-formatted
+  - mix test
 cache:
   directories:
     - deps

mix.exs

@@ -5,7 +5,7 @@ defmodule Hunter.Mixfile do
     [
       app: :hunter,
       version: "0.5.0-dev",
-      elixir: "~> 1.3",
+      elixir: "~> 1.6",
       docs: docs(),
       package: package(),
       source_url: "https://github.com/milmazz/hunter",