Set swift version in podspec

Author: jberkel

SQLite.swift.podspec

@@ -26,7 +26,7 @@ Pod::Spec.new do |s|
   s.watchos.deployment_target = "2.0"
   s.default_subspec  = 'standard'
   s.pod_target_xcconfig = {
-    'SWIFT_VERSION' => '2.3',
+    'SWIFT_VERSION' => '3.0',
   }
 
   s.subspec 'standard' do |ss|