Update license and add missing error

Author: milindl

LICENSE.txt

@@ -1,6 +1,5 @@
 The MIT License (MIT)
-Copyright (c) 2016-2023 Blizzard Entertainment
-              2023      Confluent, Inc.
+Copyright (c) 2023 Confluent, Inc.
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of
 this software and associated documentation files (the "Software"), to deal in

lib/kafkajs/_consumer.js

@@ -213,6 +213,10 @@ class Consumer {
     }
 
     if (Object.hasOwn(this.#kJSConfig, 'partitionAssignors')) {
+      if (!Array.isArray(this.#kJSConfig.partitionAssignors)) {
+        throw new error.KafkaJSError(CompatibilityErrorMessages.partitionAssignors(), { code: error.ErrorCodes.ERR__INVALID_ARG });
+      }
+
       this.#kJSConfig.partitionAssignors.forEach(assignor => {
         if (typeof assignor !== 'string')
           throw new error.KafkaJSError(CompatibilityErrorMessages.partitionAssignors(), { code: error.ErrorCodes.ERR__INVALID_ARG });