Updating the dependencies in AdMob to work around a bug, and mentioned the issue in the readme.md file's release notes.

Firebase C++ SDK 5.7.0

PiperOrigin-RevId: 244430802

Author: amablue

Android/firebase_dependencies.gradle

@@ -15,7 +15,8 @@
 // A map of library to the dependencies that need to be added for it.
 def firebaseDependenciesMap = [
   'app' : ['com.google.firebase:firebase-core:16.0.8'],
-  'admob' : ['com.google.firebase:firebase-ads:17.2.0'],
+  'admob' : ['com.google.firebase:firebase-ads:17.2.0',
+             'com.google.android.gms:play-services-measurement-sdk-api:16.4.0'],
   'analytics' : ['com.google.firebase:firebase-analytics:16.4.0'],
   'auth' : ['com.google.firebase:firebase-auth:16.2.1'],
   'database' : ['com.google.firebase:firebase-database:16.1.0'],

release_build_files/Android/firebase_dependencies.gradle

@@ -15,7 +15,8 @@
 // A map of library to the dependencies that need to be added for it.
 def firebaseDependenciesMap = [
   'app' : ['com.google.firebase:firebase-core:16.0.8'],
-  'admob' : ['com.google.firebase:firebase-ads:17.2.0'],
+  'admob' : ['com.google.firebase:firebase-ads:17.2.0',
+             'com.google.android.gms:play-services-measurement-sdk-api:16.4.0'],
   'analytics' : ['com.google.firebase:firebase-analytics:16.4.0'],
   'auth' : ['com.google.firebase:firebase-auth:16.2.1'],
   'database' : ['com.google.firebase:firebase-database:16.1.0'],