restrict rack version to less than 3.0 when grape version 1.8 or lower

Author: Dhruv Paranjape

Gemfile

@@ -19,7 +19,12 @@ group :development, :test do
   gem 'pry', platforms: [:mri]
   gem 'pry-byebug', platforms: [:mri]
 
-  gem 'rack'
+  if ENV.fetch('GRAPE_VERSION', '2.0.0') == 'HEAD' || Gem::Version.new(ENV.fetch('GRAPE_VERSION', '2.0.0')) >= Gem::Version.new('2.0.0')
+    gem 'rack', '>= 3.0'
+  else
+    gem 'rack', '< 3.0'
+  end
+
   gem 'rack-cors'
   gem 'rack-test'
   gem 'rake'