Remove duplicated Gemfile change for Ruby under 2.4

Author: benoittgt

example_app_generator/generate_app.rb

@@ -42,15 +42,11 @@
     if RUBY_VERSION < "2.4"
       gsub_file "Gemfile", /.*capybara.*/, "gem 'capybara', '~> 3.15.0'"
     end
-
     if Rails::VERSION::STRING >= "5.2.0" && RUBY_VERSION < '2.3.0'
       gsub_file "Gemfile", /.*chromedriver-helper.*/, "gem 'webdrivers', '< 4.0.0'"
     else
       gsub_file "Gemfile", /.*chromedriver-helper.*/, "gem 'webdrivers'"
     end
-    if RUBY_VERSION < "2.4"
-      gsub_file "Gemfile", /.*capybara.*/, "gem 'capybara', '~> 3.15.0'"
-    end
   end
 
   if Rails::VERSION::STRING >= '5.2.0' && Rails::VERSION::STRING < '6'