Update README.md (#1437)

s/AdMon/AdMob

Author: nohe427

admob/README.md

@@ -15,7 +15,7 @@ Getting Started
 
 - [Add Firebase to your Android Project](https://firebase.google.com/docs/android/setup).
 - Configure your AdMob app id:
-  - In `src/main/res/values/strings.xml` change the `admob_app_id` string to your AdMon app id.
+  - In `src/main/res/values/strings.xml` change the `admob_app_id` string to your AdMob app id.
   - Note that this ID is used in two places: `AndroidManifest.xml` and `MainActivity`
 - Run the sample on your Android device or emulator.
 - The running sample displays a test banner ad and a test interstitial add.