Update Matplotlib documentation (3.7.1)

lib/docs/scrapers/matplotlib.rb

@@ -16,7 +16,7 @@ module Docs
     options[:skip] = %w(api_changes.html tutorial.html faq.html)
 
     options[:attribution] = <<-HTML
-      &copy; 2012&ndash;2022 Matplotlib Development Team. All rights reserved.<br>
+      &copy; 2012&ndash;2023 Matplotlib Development Team. All rights reserved.<br>
       Licensed under the Matplotlib License Agreement.
     HTML