changes for ios app store release

ios/Podfile

@@ -40,5 +40,12 @@ 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['GCC_PREPROCESSOR_DEFINITIONS'] ||= [
+            '$(inherited)',
+            'AUDIO_SESSION_MICROPHONE=0'
+          ]
+        end
   end
 end