Use swift_versions DSL instead of .swift-version file.

Author: dnkoutso

.swift-version

@@ -27,6 +27,7 @@ All notable changes to this project will be documented in this file. Changes not
 - Set the version of the HTTP Server based in the project version in the **Info.plist** for macOS, iOS and tvOS platforms. ([#416](https://github.com/httpswift/swifter/pull/416)) by [@Vkt0r](https://github.com/Vkt0r)
 - Update `HttpParser` so it percent-encodes the URL components before initializing `URLComponents`. ([#423](https://github.com/httpswift/swifter/pull/423)) by [@nejcvivod](https://github.com/nejcvivod)
 - Update `SwifterTestsHttpParser` with a test for parsing bracketed query strings. ([#423](https://github.com/httpswift/swifter/pull/423)) by [@nejcvivod](https://github.com/nejcvivod)
+- Use `swift_version` CocoaPods DSL. ([#425](https://github.com/httpswift/swifter/pull/425)) by [@dnkoutso](https://github.com/dnkoutso)
 
 # [1.4.7] 
 

CHANGELOG.md

@@ -11,5 +11,6 @@ Pod::Spec.new do |s|
   s.tvos.deployment_target = "9.0"
   s.source                = { :git => "https://github.com/httpswift/swifter.git", :tag => "1.4.7" }
   s.source_files          = 'XCode/Sources/*.{swift}'
+  s.swift_version         = '4.2'
 
 end