10.21.0

Upgrading select packages to 10.21.0:

AdamE.Firebase.iOS.Core
AdamE.Firebase.iOS.Installations
AdamE.Firebase.iOS.Storage
AdamE.Firebase.iOS.CloudMessaging
AdamE.Firebase.iOS.CloudFunctions
AdamE.Firebase.iOS.CloudFirestore
AdamE.Firebase.iOS.Auth
AdamE.Firebase.iOS.Analytics
AdamE.Firebase.iOS.Crashlytics

-alpha versions have also been published (pending community validation) for:
AdamE.Firebase.iOS.ABTesting
AdamE.Firebase.iOS.RemoteConfig
AdamE.Firebase.iOS.DynamicLinks