fixes #8915

[hcientist]

changed link to https://github.com/fastlane/examples instead of https://github.com/fastlane/setups/blob/master/samples-ios/distribute-beta-build.md

Checklist

• I've run bundle exec rspec from the root directory to see all new and existing tests pass
• I've followed the fastlane code style and run bundle exec rubocop -a to ensure the code style is valid
• I've read the Contribution Guidelines
• I've updated the documentation if necessary.