Set deployment_target to 6.0

@@ -13,7 +13,7 @@ Pod::Spec.new do |m|
   m.source = { :git => 'https://github.com/sputnik-ru/Mapbox-iOS-SDK.git', :tag => m.version.to_s }
 
   m.platform              = :ios
-  m.ios.deployment_target = '5.0'
+  m.ios.deployment_target = '6.0'
   m.requires_arc          = true
 
   m.module_name = 'Mapbox_iOS_SDK'