update ios

ios/Podfile

@@ -1,5 +1,5 @@
 # Uncomment this line to define a global platform for your project
-# platform :ios, '11.0'
+platform :ios, '12.1'
 
 # CocoaPods analytics sends network stats synchronously affecting flutter build latency.
 ENV['COCOAPODS_DISABLE_STATS'] = 'true'
@@ -40,5 +40,8 @@ end
 post_install do |installer|
   installer.pods_project.targets.each do |target|
     flutter_additional_ios_build_settings(target)
+    target.build_configurations.each do |config|
+      config.build_settings['IPHONEOS_DEPLOYMENT_TARGET'] = '12.1'
+    end
   end
 end