fix: Ruby 2.7 deprecation warning on find_in_batches

Author: chrisyuska

elasticsearch-model/lib/elasticsearch/model/adapters/active_record.rb

@@ -85,7 +85,7 @@ def __find_in_batches(options={}, &block)
             scope = scope.__send__(named_scope) if named_scope
             scope = scope.instance_exec(&query) if query
 
-            scope.find_in_batches(options) do |batch|
+            scope.find_in_batches(**options) do |batch|
               batch = self.__send__(preprocess, batch) if preprocess
               yield(batch) if batch.present?
             end