Add Ruby version to engines for Rubocop

> This ensures that RuboCop is using the same Ruby version as the gem.

https://www.rubydoc.info/gems/rubocop/RuboCop/Cop/Gemspec/RequiredRubyVersion

.rubocop_todo.yml

@@ -6,16 +6,6 @@
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 4
-# Configuration parameters: Severity, Include.
-# Include: **/*.gemspec
-Gemspec/RequiredRubyVersion:
-  Exclude:
-    - 'engines/catalog/catalog.gemspec'
-    - 'engines/dfc_provider/dfc_provider.gemspec'
-    - 'engines/order_management/order_management.gemspec'
-    - 'engines/web/web.gemspec'
-
 # Offense count: 9
 # This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: AllowMultipleStyles, EnforcedHashRocketStyle, EnforcedColonStyle, EnforcedLastArgumentHashStyle.

engines/catalog/catalog.gemspec

@@ -10,6 +10,8 @@ Gem::Specification.new do |s|
   s.authors     = ["developers@ofn"]
   s.summary     = "Catalog domain of the OFN solution."
 
+  s.required_ruby_version = File.read(File.expand_path("../../.ruby-version", __dir__)).chomp
+
   s.files = Dir["{app,config,db,lib}/**/*"] + ["LICENSE.txt", "Rakefile", "README.rdoc"]
   s.metadata['rubygems_mfa_required'] = 'true'
 end

engines/dfc_provider/dfc_provider.gemspec

@@ -13,6 +13,8 @@ Gem::Specification.new do |spec|
   spec.summary     = 'Provides an API stack implementing DFC semantic ' \
                      'specifications'
 
+  spec.required_ruby_version = File.read(File.expand_path("../../.ruby-version", __dir__)).chomp
+
   spec.files = Dir["{app,config,lib}/**/*"] + ['README.md']
 
   spec.add_dependency 'active_model_serializers', '~> 0.8.4'

engines/order_management/order_management.gemspec

@@ -10,6 +10,8 @@ Gem::Specification.new do |s|
   s.authors     = ["developers@ofn"]
   s.summary     = "Order Management domain of the OFN solution."
 
+  s.required_ruby_version = File.read(File.expand_path("../../.ruby-version", __dir__)).chomp
+
   s.files = Dir["{app,config,db,lib}/**/*"] + ["LICENSE.txt", "Rakefile", "README.rdoc"]
   s.metadata['rubygems_mfa_required'] = 'true'
 end

engines/web/web.gemspec

@@ -10,6 +10,8 @@ Gem::Specification.new do |s|
   s.authors     = ["developers@ofn"]
   s.summary     = "Web domain of the OFN solution."
 
+  s.required_ruby_version = File.read(File.expand_path("../../.ruby-version", __dir__)).chomp
+
   s.files = Dir["{app,config,db,lib}/**/*"] + ["LICENSE.txt", "Rakefile", "README.rdoc"]
   s.metadata['rubygems_mfa_required'] = 'true'
 end