[Release] Update versions for Release 10.20.0 #5905

Job	Run time
specs_checking	56s
specs_testing (FirebaseABTesting.podspec)	7m 59s
specs_testing (FirebaseAnalytics.podspec)	6m 4s
specs_testing (FirebaseAnalyticsSwift.podspec)	1m 28s
specs_testing (GoogleAppMeasurement.podspec)	5m 7s
specs_testing (FirebaseAppCheck.podspec)	9m 9s
specs_testing (FirebaseAppDistribution.podspec)	5m 26s
specs_testing (FirebaseAuth.podspec)	12m 35s
specs_testing (FirebaseCore.podspec)	11m 5s
specs_testing (FirebaseCrashlytics.podspec)	15m 11s
specs_testing (FirebaseDatabase.podspec)	11m 21s
specs_testing (FirebaseDatabaseSwift.podspec)	1m 18s
specs_testing (FirebaseDynamicLinks.podspec)	9m 6s
specs_testing (FirebaseFirestore.podspec)	55m 37s
specs_testing (FirebaseFirestoreSwift.podspec)	1m 32s
specs_testing (FirebaseInAppMessaging.podspec)	5m 52s
specs_testing (FirebaseInAppMessagingSwift.podspec)	1m 46s
specs_testing (FirebaseInstallations.podspec)	11m 10s
specs_testing (FirebaseMessaging.podspec)	14m 46s
specs_testing (FirebaseMLModelDownloader.podspec)	18m 46s
specs_testing (FirebasePerformance.podspec)	8m 16s
specs_testing (FirebaseRemoteConfig.podspec)	9m 36s
specs_testing (FirebaseRemoteConfigSwift.podspec)	1m 24s
specs_testing (FirebaseSharedSwift.podspec)	4m 49s
specs_testing (FirebaseStorage.podspec)	12m 16s
	4h 2m 35s

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