[CI] Adds HTML reporter to xpack specs

Author: picandocodigo

elasticsearch-xpack/spec/spec_helper.rb

@@ -51,4 +51,8 @@ def self.included(context)
   config.formatter = 'documentation'
   config.color = true
   config.add_formatter('RspecJunitFormatter', '../elasticsearch-api/tmp/elasticsearch-xpack-junit.xml')
+  config.add_formatter(
+    'RSpec::Core::Formatters::HtmlFormatter',
+    "tmp/elasticsearch-#{ENV['TEST_SUITE']}-#{RUBY_VERSION}.html"
+  )
 end