Upgrade to Ruby 3.0.5

[briri]

Fixes #3225

• Upgrade to Ruby version 3.0.5
• Bumped all Github actions to use ruby 3.0
• Cleaned up Gemfile by:
  • removing gems that were already commented out
  • removed selenium-webdriver and capybara-webmock
  • removing version restrictions on: danger, font-awesome-sass, webdrivers
• Ran into issue with @import 'font-awesome-sprockets'; line in app/assets/stylesheets/application.scss. Removed that line after referring to the latest font-awesome install/setup guide which no longer includes it.
• Updated places that were incorrectly using keyword args. See this article for an overview
• Removed .freeze from Regex and Range constants since those types are already immutable
• Fixed Rubocop complaint about redundancy of r.nil? ? nil : r.user, so changed it to r&.user in app/models/plan.rb
• Fixed Rubocop complaint about redundant :: in config.log_formatter = ::Logger::Formatter.new in config/environments/production.rb
• Froze deprecator constants that were Strings
• Cleaned up spec/rails_helper.rb and spec/spec_helper.rb
• Simplified the spec/support/capybara.rb helper to work with the latest version of Capybara and use its built in headless Chrome driver

[benjaminfaure]

The PR includes an upgrade to FontAwesome (from 5 to 6). Was there any problem with the icons ?
With the upgrade from 4 to 5, a lot of icons had to be renamed

[briri]

I will have to check, the column sorts looked ok. I will do a more thorough check though.

[pengyin-shan]

@briri the CHANGELOG looks good to me. It described the content of the PR very well. After your PR is merged into the development branch, whoever wants to submit another PR will attach more stuff after your updates.

Then when the v4.1.0 got released, the release can just copy and paste our CHANGELOG to release notes.

[briri]

great! thanks for reviewing it @pengyin-shan