Change Firestore Podspec for tvos

Author: a-maurice

firestore/integration_test/Podfile

@@ -10,7 +10,7 @@ end
 
 target 'integration_test_tvos' do
   platform :tvos, '15.0'
-  pod 'Firebase/Firestore', '12.0.0'
+  pod 'FirebaseFirestore', '12.0.0'
   pod 'Firebase/Auth', '12.0.0'
 end
 

firestore/integration_test_internal/Podfile

@@ -10,7 +10,7 @@ end
 
 target 'integration_test_tvos' do
   platform :tvos, '15.0'
-  pod 'Firebase/Firestore', '12.0.0'
+  pod 'FirebaseFirestore', '12.0.0'
   pod 'Firebase/Auth', '12.0.0'
 end