It’s recommended to use a Gemfile instead of using an indeterministic
gem install fastlane on the CI system each time to ensure the fastlane
dependencies are stable and reproducible between local and cloud machines.
However, this step is optional.
    
      In both your [project]/android and [project]/ios folders, create a
Gemfile containing the following content:
        
  source "https://rubygems.org"

  gem "fastlane"
        
      
      In both directories, run bundle update and check both Gemfile and
Gemfile.lock into source control.
      When running locally, use bundle exec fastlane instead of fastlane.