Custom sound not working in IOS 10

WARNING: IF YOU IGNORE THIS TEMPLATE, WE'LL IGNORE YOUR ISSUE. YOU MUST FILL THIS IN!

Provide a general summary of the issue.

Your Environment

cli packages: (/usr/local/lib/node_modules)

@ionic/cli-utils  : 1.9.2
ionic (Ionic CLI) : 3.9.2

global packages:

Cordova CLI : 7.0.1

local packages:

@ionic/app-scripts : 2.1.3
Cordova Platforms  : ios 4.4.0
Ionic Framework    : ionic-angular 3.6.0

System:

ios-sim : 6.0.0 
Node    : v8.1.2
npm     : 4.6.1 
OS      : macOS Sierra
Xcode   : Xcode 8.3.3 Build version 8E3004b

Plugin version: 0.8.5
Platform: IOS
OS version: macOS Sierra
Device manufacturer / model: IOS simulator iphone SE
Cordova version (cordova -v): 7.0.1
Cordova platform version (cordova platform ls): ios 4.4.0
Plugin config
Ionic Version (if using Ionic) 3.9.2

Expected Behavior

The notification should play the desire sound

Actual Behavior

the notification does not play the desire sound, no sound at all

Steps to Reproduce

the song.wav is in www/audio

let options = {
        id: this.info.id,
        title: this.info.title,
        text: this.info.message,
        at: new Date(this.info.enddate),
        sound: 'file://audio/song.wav',
    };
this.localNotifications.schedule(options);

Context

make the notification to play the desire sound

Debug logs

Include iOS / Android logs

ios XCode logs
Android: $ adb logcat

katzer / cordova-plugin-local-notifications

Custom sound not working in IOS 10 #1375