remove 'BILLING' unnecessary permission

FAQ.md

@@ -11,7 +11,6 @@ At the bottom you can find how to ask other questions, request features and repo
 * have full network access (INTERNET): to send and receive email
 * view network connections (ACCESS_NETWORK_STATE): to monitor internet connectivity changes
 * run at startup (RECEIVE_BOOT_COMPLETED): to start monitoring on device start
-* in-app billing (BILLING): to allow in-app purchases
 * foreground service (FOREGROUND_SERVICE): to run a foreground service on Android 9 Pie and later, see also the next question
 * prevent device from sleeping (WAKE_LOCK): to keep the device awake while synchronizing messages
 * Optional: read your contacts (READ_CONTACTS): to autocomplete addresses and to show photos

app/src/main/AndroidManifest.xml

@@ -9,7 +9,6 @@
     <uses-permission android:name="android.permission.GET_ACCOUNTS" />
     <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
     <uses-permission android:name="android.permission.WAKE_LOCK" />
-    <uses-permission android:name="com.android.vending.BILLING" />
 
     <uses-feature
         android:name="android.software.app_widgets"