Allow ruby version 4.0 in gemspec

[obrie]

This adds support for Ruby 4.0. Note this is currently broken for flatware-cucumber due to a change in Ruby that was fixed here: cucumber/cucumber-ruby-core#302

Opening this PR to start a discussion around how you want to move forward to address this. We could change the minimum version require for flatware-cucumber. I haven't spent time thinking through potential alternatives yet. Example of failure:

  1) Flatware::Cucumber.configure copies the arguments into each job
     Failure/Error: cli_config.parse! args + %w[--format Flatware::Cucumber::Formatter]
     
     Cucumber::Cli::YmlLoadError:
       cucumber.yml was found, but could not be parsed with ERB.  Please refer to cucumber's documentation on correct profile usage.
       #<ArgumentError: wrong number of arguments (given 3, expected 1)>
     # ./lib/flatware/cucumber.rb:38:in 'Flatware::Cucumber.configure'
     # ./spec/flatware/cucumber_spec.rb:7:in 'block (3 levels) in <top (required)>'
     # ------------------
     # --- Caused by: ---
     # ArgumentError:
     #   wrong number of arguments (given 3, expected 1)
     #   ./lib/flatware/cucumber.rb:38:in 'Flatware::Cucumber.configure'

  2) Flatware::Cucumber run with multiple scenarios in the same file calls the steps the correct number of times
     Failure/Error: puts event.inspect
     
     ArgumentError:
       wrong number of arguments (given 5, expected 2)
     # ./lib/flatware/cucumber/formatter.rb:53:in 'Kernel#inspect'
     # ./lib/flatware/cucumber/formatter.rb:53:in 'Flatware::Cucumber::Formatter#on_step_activated'
     # ./lib/flatware/cucumber.rb:44:in 'Flatware::Cucumber.run'
     # ./spec/flatware/cucumber_spec.rb:39:in 'block (5 levels) in <top (required)>'
     # ./spec/flatware/cucumber_spec.rb:38:in 'Dir.chdir'
     # ./spec/flatware/cucumber_spec.rb:38:in 'block (4 levels) in <top (required)>'

[obrie]

When running this on newer versions of cucumber, we get:

  1) Flatware::Cucumber run with multiple scenarios in the same file calls the steps the correct number of times
     Failure/Error: expect(Flatware).to have_received(:ran).with(3)
     
       Flatware received :ran with unexpected arguments
         expected: (3)
              got: (1) (1 time)
                   (2) (1 time)
     # ./spec/flatware/cucumber_spec.rb:47:in 'block (5 levels) in <top (required)>'
     # ./spec/flatware/cucumber_spec.rb:41:in 'Dir.chdir'
     # ./spec/flatware/cucumber_spec.rb:41:in 'block (4 levels) in <top (required)>'

I haven't quite figured that one out either.