Add missing level_override instance variable from logger 1.6.0

compatibility for most recent, included in ruby 3.3.3 logger.
ruby/logger@7aabb0b

Author: choosen

lib/aws_lambda_ric/logger_patch.rb

@@ -16,6 +16,7 @@ def initialize(logdev, shift_age = 0, shift_size = 1048576, level: 'debug',
       self.datetime_format = datetime_format
       self.formatter = formatter
       @logdev = AwsLambdaRuntimeInterfaceClient::TelemetryLoggingHelper.telemetry_log_sink
+      @level_override = {}
     end
   end
 end