Fix Swift version in podspec

Author: qmathe

DistancePicker.podspec

@@ -10,7 +10,7 @@ Pod::Spec.new do |s|
   s.author             = { "Quentin Mathé" => "[email protected]" }
   s.social_media_url   = "http://twitter.com/quentin_mathe"
 
-  s.swift_version = "4.2"
+  s.swift_version = "5.0"
   s.platform     = :ios, "8.0"
 
   s.source       = { :git => "https://github.com/qmathe/DistancePicker.git", :tag => "0.8.4" }