pod using swift version

pod_using_swift_version.rb

swift_targets_map = {
    "Charts" => "4.1"
}

post_install do |installer|
  installer.pods_project.targets.each do |target|
    target.build_configurations.each do |config|
        version = swift_targets_map[target.name]
        if version
            puts "#{target} using Swift #{version}"
            config.build_settings['SWIFT_VERSION'] = version
        end
    end
  end
end