fastlane: delivery init/run error: `setup_screenshots_for': [!] undefined method `fetch' for nil:NilClass (NoMethodError)

New Issue Checklist

• Updated fastlane to the latest version
• I have read the Contribution Guidelines

Issue Description

Issue when trying to run deliver init or deliver run

Notes: Apple recently updated their iTunes Connect webUI to include something called Media Manager

Side note, Apple also seems to require iPad Pro screenshot(s) as of today, if you support iPad.

Complete output when running fastlane, including the stack trace and command used

/Library/Ruby/Gems/2.0.0/gems/spaceship-0.29.1/lib/spaceship/tunes/app_version.rb:546:in `setup_screenshots_for': [!] undefined method `fetch' for nil:NilClass (NoMethodError)
    from /Library/Ruby/Gems/2.0.0/gems/spaceship-0.29.1/lib/spaceship/tunes/app_version.rb:540:in `block in setup_screenshots'
    from /Library/Ruby/Gems/2.0.0/gems/spaceship-0.29.1/lib/spaceship/tunes/app_version.rb:538:in `each'
    from /Library/Ruby/Gems/2.0.0/gems/spaceship-0.29.1/lib/spaceship/tunes/app_version.rb:538:in `setup_screenshots'
    from /Library/Ruby/Gems/2.0.0/gems/spaceship-0.29.1/lib/spaceship/tunes/app_version.rb:303:in `setup'
    from /Library/Ruby/Gems/2.0.0/gems/spaceship-0.29.1/lib/spaceship/base.rb:182:in `initialize'
    from /Library/Ruby/Gems/2.0.0/gems/spaceship-0.29.1/lib/spaceship/tunes/app_version.rb:158:in `new'
    from /Library/Ruby/Gems/2.0.0/gems/spaceship-0.29.1/lib/spaceship/tunes/app_version.rb:158:in `factory'
    from /Library/Ruby/Gems/2.0.0/gems/spaceship-0.29.1/lib/spaceship/tunes/app_version.rb:180:in `find'
    from /Library/Ruby/Gems/2.0.0/gems/spaceship-0.29.1/lib/spaceship/tunes/application.rb:102:in `edit_version'
    from /Library/Ruby/Gems/2.0.0/gems/spaceship-0.29.1/lib/spaceship/tunes/application.rb:108:in `latest_version'
    from /Library/Ruby/Gems/2.0.0/gems/deliver-1.13.1/lib/deliver/setup.rb:27:in `generate_deliver_file'
    from /Library/Ruby/Gems/2.0.0/gems/deliver-1.13.1/lib/deliver/setup.rb:6:in `run'
    from /Library/Ruby/Gems/2.0.0/gems/deliver-1.13.1/lib/deliver/commands_generator.rb:75:in `block (2 levels) in run'
    from /Library/Ruby/Gems/2.0.0/gems/commander-4.3.5/lib/commander/command.rb:178:in `call'
    from /Library/Ruby/Gems/2.0.0/gems/commander-4.3.5/lib/commander/command.rb:178:in `call'
    from /Library/Ruby/Gems/2.0.0/gems/commander-4.3.5/lib/commander/command.rb:153:in `run'
    from /Library/Ruby/Gems/2.0.0/gems/commander-4.3.5/lib/commander/runner.rb:428:in `run_active_command'
    from /Library/Ruby/Gems/2.0.0/gems/fastlane_core-0.50.0/lib/fastlane_core/ui/fastlane_runner.rb:36:in `run!'
    from /Library/Ruby/Gems/2.0.0/gems/commander-4.3.5/lib/commander/delegates.rb:15:in `run!'
    from /Library/Ruby/Gems/2.0.0/gems/deliver-1.13.1/lib/deliver/commands_generator.rb:132:in `run'
    from /Library/Ruby/Gems/2.0.0/gems/deliver-1.13.1/lib/deliver/commands_generator.rb:12:in `start'
    from /Library/Ruby/Gems/2.0.0/gems/deliver-1.13.1/bin/deliver:5:in `<top (required)>'
    from /usr/bin/deliver:23:in `load'
    from /usr/bin/deliver:23:in `<main>'

Configuration Files

Please copy the complete content of your Fastfile and any other configuration files you use below:

Fastfile:

# INSERT CONTENT HERE

Environment

fastlane version (run fastlane -v): fastlane 1.99.0

Do you use bundler to execute fastlane (i.e. bundle exec fastlane)? No

Do you use a Ruby environment manager (e.g. chruby, rbenv, rvm)? No