support for swift 5.0 and Xcode 10.2

[patrick piemonte]

support for swift 5.0 and Xcode 10.2

[patrick piemonte]

With Xcode 10.2, one of Poly's dependencies currently requires this script in your Podfile post install.

This is only required until this PR has landed.

post_install do |installer|
  installer.pods_project.targets.each do |target|
    if target.name == 'Cache'
      target.build_configurations.each do |config|
        level = '-Osize'
        config.build_settings['SWIFT_OPTIMIZATION_LEVEL'] = level
        puts "Set #{target.name} #{config.name} to Optimization Level #{level}"
      end
    end
  end
end

[patrick piemonte]

https://support.google.com/poly/answer/10192635