Make SAX Parser nokogiri 17 compatible

Due to changes in nokogiri 17, the SAX parser now needs a default
encoding: sparklemotion/nokogiri#3288

Author: bihorco36

lib/prawn/markup/processor.rb

@@ -49,7 +49,9 @@ def parse(html)
 
         reset
         html = Prawn::Markup::Normalizer.new(html).normalize
-        Nokogiri::HTML::SAX::Parser.new(self).parse(html) { |ctx| ctx.recovery = true }
+        Nokogiri::HTML::SAX::Parser.new(self, 'UTF-8').parse(html) do |ctx|
+          ctx.recovery = true
+        end
       end
 
       def start_element(name, attrs = [])