Revert deprecating Ruby 2.5 & Ruby 2.6

This commit reverts part of 0cd2431

Even if we now support Rails 7, which only works from Ruby 2.7 onwards,
we also still support Rails 5.2, which works from Ruby 2.5.

Deprecating Ruby versions is a backward incompatible change, so we'll
do that in major releases.

api/solidus_api.gemspec

@@ -20,7 +20,7 @@ Gem::Specification.new do |s|
  f.match(%r{^(spec|script)/})
  end
 
- s.required_ruby_version = '>= 2.7.0'
+ s.required_ruby_version = '>= 2.5.0'
  s.required_rubygems_version = '>= 1.8.23'
 
  s.add_dependency 'jbuilder', '~> 2.8'

backend/solidus_backend.gemspec

@@ -20,7 +20,7 @@ Gem::Specification.new do |s|
  f.match(%r{^(spec|script)/})
  end
 
- s.required_ruby_version = '>= 2.7.0'
+ s.required_ruby_version = '>= 2.5.0'
  s.required_rubygems_version = '>= 1.8.23'
 
  s.add_dependency 'solidus_api', s.version

core/solidus_core.gemspec

@@ -20,7 +20,7 @@ Gem::Specification.new do |s|
  f.match(%r{^(spec|script)/})
  end
 
- s.required_ruby_version = '>= 2.7.0'
+ s.required_ruby_version = '>= 2.5.0'
  s.required_rubygems_version = '>= 1.8.23'
 
  %w[

frontend/solidus_frontend.gemspec

@@ -20,7 +20,7 @@ Gem::Specification.new do |s|
  f.match(%r{^(spec|script)/})
  end
 
- s.required_ruby_version = '>= 2.7.0'
+ s.required_ruby_version = '>= 2.5.0'
  s.required_rubygems_version = '>= 1.8.23'
 
  s.add_dependency 'solidus_api', s.version

sample/solidus_sample.gemspec

@@ -20,7 +20,7 @@ Gem::Specification.new do |s|
  f.match(%r{^(spec|script)/})
  end
 
- s.required_ruby_version = '>= 2.7.0'
+ s.required_ruby_version = '>= 2.5.0'
  s.required_rubygems_version = '>= 1.8.23'
 
  s.add_dependency 'solidus_core', s.version

solidus.gemspec

@@ -18,7 +18,7 @@ Gem::Specification.new do |s|
 
  s.files = Dir['README.md', 'lib/**/*']
 
- s.required_ruby_version = '>= 2.7.0'
+ s.required_ruby_version = '>= 2.5.0'
  s.required_rubygems_version = '>= 1.8.23'
 
  s.add_dependency 'solidus_api', s.version