Update Bootstrap documentation (5.1)

lib/docs/filters/bootstrap/entries_v5.rb

@@ -20,7 +20,7 @@ module Docs
         entries = []
 
         # titles
-        css('h2', 'h3').each do |node|
+        css('h2:not(.accordion-header)', 'h3').each do |node|
           entries << [ name + ': ' + node.content, node['id']]
         end
 

lib/docs/scrapers/bootstrap.rb

@@ -17,7 +17,7 @@ module Docs
     HTML
 
     version '5' do
-      self.release = '5.0'
+      self.release = '5.1'
       self.base_url = "https://getbootstrap.com/docs/#{self.release}/"
       self.root_path = 'getting-started/introduction/'