update podspec

Author: liuxuan30

Charts.podspec

@@ -1,16 +1,16 @@
 Pod::Spec.new do |s|
   s.name = "Charts"
-  s.version = "3.5.0"
+  s.version = "3.6.0"
   s.summary = "Charts is a powerful & easy to use chart library for iOS, tvOS and OSX (and Android)"
   s.homepage = "https://github.com/danielgindi/Charts"
   s.license = { :type => "Apache License, Version 2.0", :file => "LICENSE" }
   s.authors = "Daniel Cohen Gindi", "Philipp Jahoda"
-  s.ios.deployment_target = "8.0"
+  s.ios.deployment_target = "9.0"
   s.tvos.deployment_target = "9.0"
   s.osx.deployment_target = "10.11"
   s.source = { :git => "https://github.com/danielgindi/Charts.git", :tag => "v#{s.version}" }
   s.default_subspec = "Core"
-  s.swift_version = '5.0'
+  s.swift_version = '5.3'
   s.cocoapods_version = '>= 1.5.0'
 
   s.subspec "Core" do |ss|