fix: remove undef :broadcast since ActiveSupport::Logger dropped it

Author: Amnesthesia

lib/rails_semantic_logger/extensions/active_support/logger.rb

@@ -4,7 +4,7 @@ module ActiveSupport
   # More hacks to try and stop Rails from being it's own worst enemy.
   class Logger
     class << self
-      undef :logger_outputs_to?, :broadcast
+      undef :logger_outputs_to?
     end
 
     # Prevent Console from trying to merge loggers