update podspec

TwitterImagePipeline.podspec

@@ -1,14 +1,15 @@
 Pod::Spec.new do |s|
   s.name             = 'TwitterImagePipeline'
-  s.version          = '2.12.2'
-  s.compiler_flags   = '-DTIP_PROJECT_VERSION=2.12'
+  s.version          = '2.13.0'
+  s.compiler_flags   = '-DTIP_PROJECT_VERSION=2.13'
   s.summary          = 'Twitter Image Pipeline is a robust and performant image loading and caching framework for iOS'
   s.description      = 'Twitter created a framework for image loading/caching in order to fulfill the numerous needs of Twitter for iOS including being fast, safe, modular and versatile.'
   s.homepage         = 'https://github.com/twitter/ios-twitter-image-pipeline'
   s.license          = { :type => 'Apache License, Version 2.0', :file => 'LICENSE' }
   s.author           = { 'Twitter' => '[email protected]' }
   s.source           = { :git => 'https://github.com/twitter/ios-twitter-image-pipeline.git', :tag => s.version.to_s }
   s.ios.deployment_target = '8.0'
+  s.swift_versions   = [ 5.0 ]
 
   s.subspec 'Default' do |sp|
     sp.source_files = 'TwitterImagePipeline/**/*.{h,m}'