chore: iOS platform set 14.0

之前是 12.0

fix to
zhangao0086/DKImagePickerController#705 (comment)

Author: d1y

ios/Podfile

@@ -1,5 +1,5 @@
 # Uncomment this line to define a global platform for your project
-# platform :ios, '12.0'
+platform :ios, '14.0'
 
 # CocoaPods analytics sends network stats synchronously affecting flutter build latency.
 ENV['COCOAPODS_DISABLE_STATS'] = 'true'
@@ -30,6 +30,7 @@ flutter_ios_podfile_setup
 target 'Runner' do
   use_frameworks!
   use_modular_headers!
+  pod 'DKImagePickerController', '4.3.4'
 
   flutter_install_all_ios_pods File.dirname(File.realpath(__FILE__))
 end