VIM-6919: Release 2.0.0, Swift 4.2 migration (#65)

PlayerKit.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name             = 'PlayerKit'
-  s.version          = '1.4.0'
+  s.version          = '2.0.0'
   s.summary          = 'A modular video player system.'
 
   s.description      = <<-DESC
@@ -15,6 +15,8 @@ Pod::Spec.new do |s|
   s.ios.deployment_target = '8.0'
   s.tvos.deployment_target = '9.0'
 
+  s.swift_version = "4.2"
+  
   s.source_files = 'PlayerKit/Classes/**/*'
 
 end