Update Jinja documentation (3.0.x)

Author: simon04

assets/javascripts/templates/pages/about_tmpl.coffee

@@ -413,7 +413,7 @@ credits = [
     'https://raw.githubusercontent.com/facebook/jest/master/LICENSE'
   ], [
     'Jinja',
-    '2007-2020 Pallets',
+    '2007-2021 Pallets',
     'BSD',
     'https://github.com/pallets/jinja/blob/master/LICENSE.rst'
   ], [

lib/docs/scrapers/jinja.rb

@@ -9,14 +9,19 @@ class Jinja < UrlScraper
 
     html_filters.push 'jinja/entries', 'sphinx/clean_html'
 
-    options[:container] = '.body > .section'
+    options[:container] = '.body > section'
     options[:skip] = %w(integration/ switching/ faq/ changelog/ search/ genindex/)
 
     options[:attribution] = <<-HTML
-      &copy; 2007&ndash;2020 Pallets<br>
+      &copy; 2007&ndash;2021 Pallets<br>
       Licensed under the BSD 3-clause License.
     HTML
 
+    version '3.0' do
+      self.release = '3.0.x'
+      self.base_url = "https://jinja.palletsprojects.com/en/#{self.release}/"
+    end
+
     version '2.11' do
       self.release = '2.11.x'
       self.base_url = "https://jinja.palletsprojects.com/en/#{self.release}/"