Update firestore ios SDK

Author: kevmoo

tests/ios/Podfile

@@ -29,7 +29,7 @@ flutter_ios_podfile_setup
 target 'Runner' do
   use_frameworks!
   use_modular_headers!
-  pod 'FirebaseFirestore', :git => 'https://github.com/invertase/firestore-ios-sdk-frameworks.git', :tag => '12.6.0'
+  pod 'FirebaseFirestore', :git => 'https://github.com/invertase/firestore-ios-sdk-frameworks.git', :tag => '12.9.0'
 
   flutter_install_all_ios_pods File.dirname(File.realpath(__FILE__))
   target 'RunnerTests' do

tests/macos/Podfile

@@ -30,7 +30,7 @@ target 'Runner' do
   use_frameworks!
   use_modular_headers!
 
-  pod 'FirebaseFirestore', :git => 'https://github.com/invertase/firestore-ios-sdk-frameworks.git', :tag => '12.6.0'
+  pod 'FirebaseFirestore', :git => 'https://github.com/invertase/firestore-ios-sdk-frameworks.git', :tag => '12.9.0'
 
   flutter_install_all_macos_pods File.dirname(File.realpath(__FILE__))
   target 'RunnerTests' do