Merge pull request #19 from xflagstudio/ex1.8.1-amzn

[amazonlinux] upgrade to elixir 1.8.1

Author: nashimoto

Dockerfile

@@ -2,7 +2,7 @@ FROM amazonlinux:1
 
 ENV LANG en_US.UTF-8
 
-ENV ELIXIR_VERSION "1.7.3-otp-21"
+ENV ELIXIR_VERSION "1.8.1-otp-21"
 ENV ERLANG_VERSION "21.0"
 ENV ASDF_VERSION   "v0.5.1"
 ENV ASDF_DIR /opt/asdf