Update Project to Elixir v1.12

[nelsonic]

At present we are seeing the following error:

** (Mix) You're trying to run :auth on Elixir v1.11.2 but it has declared in its mix.exs file it supports only Elixir ~> 1.10.4

This is because our mix.exs file specifies 1.10.4:

auth/mix.exs

Line 8 in 5d04424

elixir: "~> 1.10.4",

Same in elixir_buildpack.config:

auth/elixir_buildpack.config

Line 2 in 5d04424

elixir_version=1.10.4

Meanwhile people running a later version of Elixir e.g. Elixir 1.11.2 sees the error.

José 👑 published v1.12.0-rc.0 yesterday 🎉 https://github.com/elixir-lang/elixir/releases so we might as well go for that.

Todo

• Update mix.exs to latest Elixir version
• Update .travis.yml to latest Elixir
• Update elixir_buildpack.config (the version used on Heroku)

[nelsonic]

1.12 released today https://news.ycombinator.com/item?id=27206656 🎉

[nelsonic]

Updated to latest:

elixir -v
Erlang/OTP 24 [erts-12.0.3] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [jit] [dtrace]

Elixir 1.12.2 (compiled with Erlang/OTP 24)

[nelsonic]

Getting an argument error after updating the version of fields: dwyl/fields#86 need to sort this first. ⏳

[nelsonic]

Next error to resolve: #146

[SimonLab]

Versions updated and deployed on Heroku with #147