In App Browser - doesn't load webpage in iOS 12

**Ionic version:**
[ ] 1.x
[ ] 2.x
[X] 3.x

**I'm submitting a ...** (check one with "x")
[x ] bug report
[ ] feature request

**Current behavior:**
Open the in app browser and the url does not load, it always shows a blank white page on iOS,
however, it is working in Android

**Expected behavior:**
Open the in app browser and load the url

**Related code:**

```
openWebPage() {
const browser = this.inAppBrowser.create("www.url.com", '_blank');
}
```

**Other information:**

**Ionic info:** (run `ionic info` from a terminal/cmd prompt and paste output below):

```
Ionic:

ionic (Ionic CLI) : 4.3.1 (C:\Users\***\AppData\Roaming\npm\node_modules\ionic)
Ionic Framework : ionic-angular 3.9.2
@ionic/app-scripts : 3.2.0

Cordova:

cordova (Cordova CLI) : not installed
Cordova Platforms : none
Cordova Plugins : not available

System:

NodeJS : v8.9.4 (C:\Program Files (x86)\nodejs\node.exe)
npm : 5.6.0
OS : Windows 10
```

Reproduce the blank page on iOS 12 using the shown openWebPage() call, then inspect the plugin's iOS implementation and compare its behavior with Android. Confirm the URL and the Ionic, Cordova, and plugin versions first; done means that the same URL loads in the iOS in-app browser without a blank page.

Written by the indexing model from the issue text.