docs(ruby): Mention Ruby 3.3 support in README

Author: Stranger6667

bindings/ruby/README.md

@@ -41,7 +41,7 @@ into:
 - Can process multiple documents in parallel
 - Works on Linux, Windows, and macOS
 - Supports HTML5 & CSS3
-- Tested on Ruby 2.7 and 3.2.
+- Tested on Ruby 2.7, 3.2, and 3.3.
 
 ## Playground