bootstrap: update to version 4.3

assets/javascripts/templates/pages/about_tmpl.coffee

@@ -123,7 +123,7 @@ credits = [
     'https://raw.githubusercontent.com/petkaantonov/bluebird/master/LICENSE'
   ], [
     'Bootstrap',
-    '2011-2018 Twitter, Inc.<br>2011-2018 The Bootstrap Authors',
+    '2011-2019 Twitter, Inc.<br>2011-2019 The Bootstrap Authors',
     'CC BY',
     'https://creativecommons.org/licenses/by/3.0/'
   ], [

lib/docs/scrapers/bootstrap.rb

@@ -8,16 +8,17 @@ module Docs
 
     options[:trailing_slash] = true
 
+    # https://github.com/twbs/bootstrap/blob/master/LICENSE
     options[:attribution] = <<-HTML
-      &copy; 2011&ndash;2018 Twitter, Inc.<br>
-      &copy; 2011&ndash;2018 The Bootstrap Authors<br>
+      &copy; 2011&ndash;2019 Twitter, Inc.<br>
+      &copy; 2011&ndash;2019 The Bootstrap Authors<br>
       Code licensed under the MIT License.<br>
       Documentation licensed under the Creative Commons Attribution License v3.0.
     HTML
 
     version '4' do
-      self.release = '4.1.3'
-      self.base_url = 'https://getbootstrap.com/docs/4.1/'
+      self.release = '4.3'
+      self.base_url = 'https://getbootstrap.com/docs/4.3/'
       self.root_path = 'getting-started/introduction/'
 
       html_filters.push 'bootstrap/entries_v4', 'bootstrap/clean_html_v4'