Remove android:allowBackup="true" from manifest

This causes a conflict if the library is used by a project with android:allowBackup="false". I see no reason why a library should set this property at all.

Author: Petter Hesselberg

src/android/src/main/AndroidManifest.xml

@@ -2,7 +2,6 @@
     package="com.RNFetchBlob">
 
     <application
-        android:allowBackup="true"
         android:label="@string/app_name"
         android:supportsRtl="true">