Apply swift version

fastlane/Fastfile

@@ -24,6 +24,7 @@ platform :ios do
     scan(
       scheme: "Kingfisher", 
       clean: true, 
+      xcargs: "SWIFT_VERSION=#{options[:swift_version]}",
       destination: options[:destination]
     )
   end
@@ -33,6 +34,7 @@ platform :ios do
       workspace: "Kingfisher.xcworkspace",
       configuration: "Debug",
       scheme: "Kingfisher",
+      xcargs: "SWIFT_VERSION=#{options[:swift_version]}",
       destination: options[:destination]
     )
   end