Update the package location URL

[philihp]

• RPM for Erlang in bin/build no longer exists. Per https://www.erlang-solutions.com/resources/download.html, the proper way to download this package is by installing their repository and then doing a yum install esl-erlang
• Updates to Elixir and Distillery

TODO: After deploying with this, checking the logs with journalctl -u distillery-example.service on one of the machines, it's not starting up with this error

Start Call: ClusterEC2.Strategy.Tags.start_link([%Cluster.Strategy.State{config: [hosts: []], connect
06:58:40.235 [error] Child Cluster.Supervisor of Supervisor Example.Supervisor failed to start
** (exit) shutdown: failed to start child: :example
** (EXIT) an exception was raised:
** (KeyError) key :ec2_tagname not found in: [hosts: []]
(elixir) lib/keyword.ex:393: Keyword.fetch!/2
(libcluster_ec2) lib/strategy/tags.ex:128: ClusterEC2.Strategy.Tags.get_nodes/1
(libcluster_ec2) lib/strategy/tags.ex:86: ClusterEC2.Strategy.Tags.load/1
(libcluster_ec2) lib/strategy/tags.ex:55: ClusterEC2.Strategy.Tags.init/1
(stdlib) gen_server.erl:374: :gen_server.init_it/2
(stdlib) gen_server.erl:342: :gen_server.init_it/6
(stdlib) proc_lib.erl:249: :proc_lib.init_p_do_apply/3

[bitwalker]

This looks great! Thanks so much for taking the time to update things, I know it can be a pain!