Merge pull request rails#52357 from Uaitt/clarify-upgrading-ruby-on-rails-guide

Clarify usafe of `bundle update` in upgrading Rails guide [ci skip]

Author: rafaelfranca

guides/source/upgrading_ruby_on_rails.md

@@ -44,8 +44,8 @@ Repeat this process until you reach your target Rails version.
 
 To move between versions:
 
-1. Change the Rails version number in the `Gemfile` and run `bundle update`.
-2. Change the versions for Rails JavaScript packages in `package.json` and run `bin/rails javascript:install` if running jsbundling-rails
+1. Change the Rails version number in the `Gemfile` and run `bundle update rails`.
+2. Change the versions for Rails JavaScript packages in `package.json` and run `bin/rails javascript:install` if running jsbundling-rails.
 3. Run the [Update task](#the-update-task).
 4. Run your tests.