Drop Node.js v5

Support for Node.js v5 was dropped at the end of June of this year and
is no longer being updated.

See: https://nodejs.org/en/blog/community/v5-to-v7/

Note that the tags for v5 versions will still be available in the
Docker Hub

Author: Christopher Horrell

5.12/Dockerfile

@@ -5,7 +5,6 @@ hash git 2>/dev/null || { echo >&2 "git not found, exiting."; }
 
 array_0_12='0';
 array_4_5='4 argon';
-array_5_12='5';
 array_6_6='6 latest';
 
 cd $(cd ${0%/*} && pwd -P);