Remove unnecessary require "async/service/supervisor/supervised".

Author: ioquatix

lib/falcon/service/server.rb

@@ -5,7 +5,6 @@
 # Copyright, 2020, by Daniel Evans.
 
 require "async/service/managed/service"
-require "async/service/supervisor/supervised"
 require "async/http/endpoint"
 
 require_relative "../server"