Configure link checker for v4

Author: dshevtsov

_config.checks.yml

@@ -3,22 +3,20 @@
 # For configuration defaults, refer to: https://github.com/gjtorikian/html-proofer/blob/master/lib/html-proofer/configuration.rb
 #
 html-proofer:
+  # Do not flag a tags missing href
+  :allow_missing_href: true
+
+  # Ignores images with missing alt tags
+  :ignore_missing_alt: true
+
+  # Ignores images with empty alt tags.
+  :empty_alt_ignore: true
 
   # Validate HTML
   :check_html: true
 
   # Do not check external links.
   :disable_external: true
 
-  # Report only errors that fall within the 4xx status code range.
-  :only_4xx: true
-
-  # Ignores images with empty alt tags.
-  :empty_alt_ignore: true
-
   # Sort errors by description in the report
   :error_sort: :desc
-
-  # Use up to 3 parallel processes to speed up internal file checks.
-  :parallel:
-    :in_processes: 3

lib/link_checker.rb

@@ -18,7 +18,7 @@ def self.options
     return config['html-proofer'] unless ENV['BUILD_NUMBER']
 
     staging_prefix = '/' + ENV['BUILD_NUMBER']
-    url_swap = { url_swap: { /\A#{staging_prefix}/ => '' } }
+    url_swap = { swap_urls: { /\A#{staging_prefix}/ => '' } }
     config['html-proofer'].merge(url_swap)
   end