Update FirebaseCore/CHANGELOG.md

Co-authored-by: rachelsaunders <[email protected]>

FirebaseCore/CHANGELOG.md

@@ -1,9 +1,11 @@
 # Firebase 11.8.0
 - [deprecated] The zip and Carthage distributions of the Google Mobile Ads SDK
   with Firebase are deprecated and will be removed in the next major release.
-  The Google Mobile Ads SDK binary distribution should be accessed from
-  https://developers.google.com/admob/ios/download. (#14408)
-
+  Instead, the Google Mobile Ads SDK binary distribution should be accessed
+  from https://developers.google.com/admob/ios/download. Note that
+  _any existing versions of the Firebase zip or Carthage distributions will
+  continue to be available and functional_. Learn more about this change
+  in our FAQ: https://firebase.google.com/support/faq/#admob-which-sdk (#14408)
 # Firebase 11.4.2
 - [fixed] CocoaPods only release to fix iOS 12 build failure resulting from
   incomplete implementation in the FirebaseCoreInternal CocoaPod.