Bump miminum cucumber version to 4

Cucumber 4 is the first version using cucumber-gherkin instead of
gherkin as a dependency. Using this as the lowest supported version
avoids conflicts between gherkin and cucumber-gherkin when installing
all appraisals.

.github/workflows/ruby.yml

@@ -24,9 +24,9 @@ jobs:
         appraisal: [cucumber_6]
         include:
           - ruby: "2.4.0"
-            appraisal: cucumber_2_4
+            appraisal: cucumber_4
           - ruby: "2.4"
-            appraisal: cucumber_3
+            appraisal: cucumber_4
           - ruby: "2.5"
             appraisal: cucumber_4
           - ruby: "2.6"

Appraisals

@@ -1,18 +1,8 @@
 # frozen_string_literal: true
 
-appraise "cucumber_2_4" do
-  gem "cucumber", "~> 2.4.0"
-  gem "childprocess", "~> 2.0.0"
-end
-
-appraise "cucumber_3" do
-  gem "cucumber", "~> 3.0"
-  gem "childprocess", "~> 2.0.0"
-end
-
 appraise "cucumber_4" do
   gem "cucumber", "~> 4.0"
-  gem "childprocess", "~> 3.0.0"
+  gem "childprocess", "~> 2.0.0"
 end
 
 appraise "cucumber_5" do

aruba.gemspec

@@ -23,7 +23,7 @@ Gem::Specification.new do |spec|
 
   spec.add_runtime_dependency "childprocess", [">= 2.0", "< 5.0"]
   spec.add_runtime_dependency "contracts", [">= 0.16.0", "< 0.18.0"]
-  spec.add_runtime_dependency "cucumber", [">= 2.4", "< 7.0"]
+  spec.add_runtime_dependency "cucumber", [">= 4.0", "< 7.0"]
   spec.add_runtime_dependency "rspec-expectations", "~> 3.4"
   spec.add_runtime_dependency "thor", "~> 1.0"
 

gemfiles/cucumber_4.gemfile

@@ -5,6 +5,6 @@ source "https://rubygems.org"
 gem "byebug", "~> 11.0", platform: :mri
 gem "pry-byebug", "~> 3.4", platform: :mri
 gem "cucumber", "~> 4.0"
-gem "childprocess", "~> 3.0.0"
+gem "childprocess", "~> 2.0.0"
 
 gemspec path: "../"