(iOS) Bump pinned Firebase SDK components to [v8.4.0 - July 20, 2021](h…

…ttps://firebase.google.com/support/release-notes/ios#version_840_-_july_20_2021)

plugin.xml

@@ -141,16 +141,16 @@
 				<source url="https://cdn.cocoapods.org/"/>
 			</config>
 			<pods use-frameworks="true">
-				<pod name="Firebase/Core" spec="8.1.1"/>
-				<pod name="Firebase/Auth" spec="8.1.1"/>
-				<pod name="Firebase/Messaging" spec="8.1.1"/>
-				<pod name="Firebase/Performance" spec="8.1.1"/>
-				<pod name="Firebase/RemoteConfig" spec="8.1.1"/>
-				<pod name="Firebase/InAppMessaging" spec="8.1.1"/>
-				<pod name="FirebaseFirestore" git="https://github.com/invertase/firestore-ios-sdk-frameworks.git" tag="8.1.1"/>
-				<pod name="Firebase/Crashlytics" spec="8.1.1"/>
-				<pod name="Firebase/Functions" spec="8.1.1"/>
-				<pod name="Firebase/Installations" spec="8.1.1"/>
+				<pod name="Firebase/Core" spec="8.4.0"/>
+				<pod name="Firebase/Auth" spec="8.4.0"/>
+				<pod name="Firebase/Messaging" spec="8.4.0"/>
+				<pod name="Firebase/Performance" spec="8.4.0"/>
+				<pod name="Firebase/RemoteConfig" spec="8.4.0"/>
+				<pod name="Firebase/InAppMessaging" spec="8.4.0"/>
+				<pod name="FirebaseFirestore" git="https://github.com/invertase/firestore-ios-sdk-frameworks.git" tag="8.4.0"/>
+				<pod name="Firebase/Crashlytics" spec="8.4.0"/>
+				<pod name="Firebase/Functions" spec="8.4.0"/>
+				<pod name="Firebase/Installations" spec="8.4.0"/>
 				<pod name="GoogleSignIn" spec="5.0.2"/>
 				<pod name="GoogleTagManager" spec="7.3.1"/>
 			</pods>