Alon Gal's notes

https://stackoverflow.com/questions/40501440/how-to-set-the-legacy-swift-version-for-each-pod-in-podfile-xcode-9-0-swift-3-2

post_install do |installer|
  installer.pods_project.targets.each do |target|
    if ['AirMapSDK', 'PhoneNumberKit', 'Lock', 'RxSwift', 'RxSwiftExt', 'RxCocoa', 'RxDataSources', 'ProtocolBuffers-Swift'].include? target.name
      target.build_configurations.each do |config|
        config.build_settings['SWIFT_VERSION'] = '3.2'
      end
    end
  end
end