Change the version number of dependencies in a pod

pod_snippet.swift

post_install do |installer|
    installer.pods_project.targets.each do |target|
        if ['RxSwift', 'RxCocoa', 'RxAlamofire', 'RxTest', 'RxBlocking'].include? target.name
            target.build_configurations.each do |config|
                config.build_settings['SWIFT_VERSION'] = '3.3'
            end
        end
    end
end