Update README.md

Updated the adb command from http to https to match what is already in the AndroidManifest.xml file

Author: zayna-shahzad

app-indexing/README.md

@@ -14,7 +14,7 @@ Getting Started
 - [Add Firebase to your Android Project](https://firebase.google.com/docs/android/setup).
 - Open the App Indexing project in Android Studio.
 - Run the sample on your Android device or emulator by issuing the following command using **adb** tool:  
-`adb shell am start -a android.intent.action.VIEW -d "http://www.example.com/articles/test" com.google.samples.quickstart.app_indexing`
+`adb shell am start -a android.intent.action.VIEW -d "https://www.example.com/articles/test" com.google.samples.quickstart.app_indexing`
 
 Result
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