Merge pull request #21 from mbta/jz/add-jason-dep

chore: Add explicit Jason dep

mix.exs

@@ -21,6 +21,7 @@ defmodule ScreensConfig.MixProject do
   # Run "mix help deps" to learn about dependencies.
   defp deps do
     [
+      {:jason, "~> 1.0"},
       {:credo, "~> 1.6.0", only: [:dev, :test]},
       {:dialyxir, "~> 1.1.0", only: [:dev, :test], runtime: false}
     ]