[Cocoapods] Update PINCache dependency to include performance improvements

Includes PINCache 3 beta (in latest PINRemoteImage release)

Author: Hannah Troisi

AsyncDisplayKit.podspec

@@ -59,7 +59,7 @@ Pod::Spec.new do |spec|
 
   spec.subspec 'PINRemoteImage' do |pin|
       pin.xcconfig = { 'GCC_PREPROCESSOR_DEFINITIONS' => '$(inherited) PIN_REMOTE_IMAGE=1' }
-      pin.dependency 'PINRemoteImage/iOS', '>= 3.0.0-beta.2'
+      pin.dependency 'PINRemoteImage/iOS', '>= 3.0.0-beta.3'
       pin.dependency 'AsyncDisplayKit/Core'
   end