Gemfile in u-attributes-2.6.0 vs Gemfile in u-attributes-2.7.0

@@ -1,36 +1,41 @@
 source 'https://rubygems.org'
 
 gem 'u-case', '~> 4.0'
 
-activemodel_version = ENV.fetch('ACTIVEMODEL_VERSION', '6.1')
+activemodel_version = ENV['ACTIVEMODEL_VERSION']
 
 activemodel = case activemodel_version
               when '3.2' then '3.2.22'
               when '4.0' then '4.0.13'
               when '4.1' then '4.1.16'
               when '4.2' then '4.2.11'
               when '5.0' then '5.0.7'
               when '5.1' then '5.1.7'
-              when '5.2' then '5.2.3'
-              when '6.0' then '6.0.0'
+              when '5.2' then '5.2.4'
+              when '6.0' then '6.0.3.4'
+              when '6.1' then '6.1.2'
               end
 
-if activemodel_version < '6.1'
-  gem 'activemodel', activemodel, require: false
-  gem 'activesupport', activemodel, require: false
-end
-
 simplecov_version =
   case RUBY_VERSION
-  when /\A2.[23]/ then '~> 0.17.1'
+  when /\A2.[23]/ then '0.17.1'
   when /\A2.4/ then '~> 0.18.5'
   else '~> 0.19'
   end
 
 group :test do
-  gem 'minitest', activemodel_version < '4.1' ? '~> 4.2' : '~> 5.0'
+  if activemodel_version
+    gem 'activesupport', activemodel, require: false
+    gem 'activemodel', activemodel, require: false
+    gem 'minitest', activemodel_version < '4.1' ? '~> 4.2' : '~> 5.0'
+  else
+    gem 'minitest', '~> 5.0'
+  end
+
   gem 'simplecov', simplecov_version, require: false
 end
+
+gem 'rake', '~> 13.0'
 
 # Specify your gem's dependencies in u-attributes.gemspec
 gemspec