Update ReactNative documentation (0.56)

Author: Thibaut

lib/docs/filters/react_native/entries.rb

@@ -12,7 +12,7 @@ def get_name
       end
 
       def get_type
-        link = at_css('.navItemActive')
+        link = at_css('.navListItemActive')
         return 'Miscellaneous' unless link
         section = link.ancestors('.navGroup').first
         type = section.at_css('h3').content.strip

lib/docs/scrapers/react_native.rb

@@ -2,7 +2,7 @@ module Docs
   class ReactNative < UrlScraper
     self.slug = 'react_native'
     self.type = 'react_native'
-    self.release = '0.55'
+    self.release = '0.56'
     self.base_url = 'https://facebook.github.io/react-native/docs/'
     self.root_path = 'getting-started.html'
     self.links = {