Attempt to fix feature specs in CI

It looks like we're hitting the same problem described at SeleniumHQ/selenium#13112

Perhaps using '--headless=new' instead of just 'headless' will fix it.

spec/rails_helper.rb

@@ -14,7 +14,7 @@
 
 Capybara.register_driver :selenium do |app|
   options = Selenium::WebDriver::Chrome::Options.new(
-    args: %w[headless no-sandbox disable-gpu --window-size=1200,1200]
+    args: %w[--headless=new no-sandbox disable-gpu --window-size=1200,1200]
   )
   Capybara::Selenium::Driver.new(app,
                                  browser: :chrome,