add some rspec configuration

spec/simple_spec.rb

@@ -2,7 +2,7 @@ require_relative "spec_helper"
 require_relative "support/app_runner"
 require_relative "support/buildpack_builder"
 
-describe "Simple" do
+RSpec.describe "Simple" do
   before(:all) do
     @debug = false
     BuildpackBuilder.new(@debug)

spec/spec_helper.rb

@@ -42,7 +42,6 @@ RSpec.configure do |config|
 
 # The settings below are suggested to provide a good initial experience
 # with RSpec, but feel free to customize to your heart's content.
-=begin
   # These two settings work together to allow you to limit a spec run
   # to individual examples or groups you care about by tagging them with
   # `:focus` metadata. When nothing is tagged with `:focus`, all examples
@@ -87,5 +86,4 @@ RSpec.configure do |config|
   # test failures related to randomization by passing the same `--seed` value
   # as the one that triggered the failure.
   Kernel.srand config.seed
-=end
 end