fix: issue where deployment targets for subspec AppCheck in Firebase podspec does not match FirebaseAppCheck podspec (#9187)

Author: Salakar

Firebase.podspec

@@ -99,9 +99,10 @@ Simplify your app development, grow your user base, and monetize more effectivel
   s.subspec 'AppCheck' do |ss|
     ss.dependency 'Firebase/CoreOnly'
     ss.dependency 'FirebaseAppCheck', '~> 8.11.0-beta'
-    ss.ios.deployment_target = '11.0'
-    ss.osx.deployment_target = '10.15'
-    ss.tvos.deployment_target = '11.0'
+    ss.ios.deployment_target = '9.0'
+    ss.osx.deployment_target = '10.12'
+    ss.tvos.deployment_target = '10.0'
+    ss.watchos.deployment_target = '6.0'
   end
 
   s.subspec 'Auth' do |ss|