Add iOs platform never stops

**Description:**
When executing the command `ionic cordova platform add ios`, it stops on "Generating platform resources: 29 / 32 complete", sometimes "31/32" but never ends. If I abort the command, I then have errors when running my ionic app on iOs.

**Steps to Reproduce:**
Execute the command `ionic cordova platform add ios`

**Output:**
> cordova platform add ios --save
✔ Running command - done!
> ionic cordova resources ios --force
[DEBUG] resourceJsonStructure=3
[DEBUG] platformEngines=ios
[DEBUG] buildPlatforms=ios
[DEBUG] getProjectPlatforms completed - length=1
[DEBUG] imgResources=32
[DEBUG] createImgDestinationDirectories completed - length=2
[DEBUG] getSourceImages completed - 2
✔ Collecting resource configuration and source images - done!
✔ Filtering out image resources that do not need regeneration - done!
[DEBUG] uploadSourceImages completed - responses=[
{},
{}
]
✔ Uploading source images to prepare for transformations - done!
⠼ Generating platform resources: 28 / 32 complete

**My `ionic info`:**
cli packages: (/usr/local/lib/node_modules)

@ionic/cli-utils : 1.12.0
ionic (Ionic CLI) : 3.12.0

global packages:

cordova (Cordova CLI) : 7.0.1

local packages:

@ionic/app-scripts : 3.0.0
Cordova Platforms : ios 4.4.0
Ionic Framework : ionic-angular 3.7.1

System:

ios-deploy : 1.9.1
Node : v7.7.2
npm : 4.1.2
OS : macOS Sierra
Xcode : Xcode 8.2.1 Build version 8C1002

Misc:

backend : pro