Fix links on README.md

Author: deisterhold

README.md

@@ -62,12 +62,11 @@ framework](https://firebase.google.com/docs/ios/setup) to your project.
 The READMEs for components of FirebaseUI can be found in their respective
 project folders.
 
-- [Auth](FirebaseAuthUI/README.md)
-- [Firestore](FirebaseFirestoreUI/README.md)
-- [PhoneAuth](FirebasePhoneAuthUI/README.md)
-- [Database](FirebaseDatabaseUI/README.md)
-- [Firestore](FirebaseFirestoreUI/README.md)
-- [Storage](FirebaseStorageUI/README.md)
+- [Auth](Auth/README.md)
+- [PhoneAuth](PhoneAuth/README.md)
+- [Database](Database/README.md)
+- [Firestore](Firestore/README.md)
+- [Storage](Storage/README.md)
 
 ## Local Setup