fix: add Lazy-load Axe::API::Run to improve boot time (#396)

It saves 95% of load time when doing `require "axe-rspec"`.

The time is actually spent loading the `virtus` library. Deferring the
loading of `Axe::API::Run` until needed does in turn defer the loading
of `virtus` library.

No QA required.

---------

Co-authored-by: Christophe Bliard <christophe.bliard@trux.info>

.circleci/config.yml

@@ -6,7 +6,7 @@ defaults: &defaults
   working_directory: ~/axe-core-gems
 
 orbs:
-  browser-tools: circleci/browser-tools@1.4.3
+  browser-tools: circleci/browser-tools@1.4.8
   node: circleci/node@5.0.0
 
 commands:

packages/axe-core-api/e2e/selenium/spec/api_spec.rb

@@ -2,10 +2,10 @@
 require "json" #TODO: REMOVE
 require "selenium-webdriver"
 require "axe/core"
-require "axe/api/run"
+require "axe/api"
 
 options = Selenium::WebDriver::Chrome::Options.new
-# options.add_argument('--headless')
+options.add_argument('--headless')
 options.add_argument('--no-sandbox')
 options.add_argument('--disable-dev-shm-usage')
 $driver = Selenium::WebDriver.for :chrome, options: options

packages/axe-core-api/lib/axe/api.rb

@@ -0,0 +1,5 @@
+module Axe
+  module API
+    autoload :Run, "axe/api/run"
+  end
+end

packages/axe-core-api/lib/axe/matchers/be_axe_clean.rb

@@ -2,7 +2,7 @@
 
 require_relative "../../chain_mail/chainable"
 require_relative "../core"
-require_relative "../api/run"
+require_relative "../api"
 
 module Axe
   module Matchers