Update a bit of the documentation of install_on_device.rb

[ls-1N]

It seems that the ios-deploy project's README.md suggests the use of brew over npm for installing their package since 2019. ios-control/ios-deploy@3714fc1

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 see several green ci/circleci builds in the "All checks have passed" section of my PR (connect CircleCI to GitHub if not)
• I've read the Contribution Guidelines
• I've updated the documentation if necessary.

Motivation and Context

Documentation includes outdated instructions

Description

Change the method of installation of the ios-deploy package suggested by fastlane documentation.

Testing Steps

[google-cla]

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[mollyIV]

Thanks for the contribution 💯

Below you'll find a link to the mentioned pull request as a reference 😉

Remove node/npm from README installation steps (in favor of brew)