no implicit conversion of nil into String for com/microsoft/json-parser.rb:3

When i install latest plug with version 0.9.13 in logstash-6.0.1, after install the plugin and start the logstash and get a logstash plugin loading error:
[2018-09-19T09:15:49,181][ERROR][logstash.plugins.registry] Problems loading a plugin with {:type=>"input", :name=>"azureblob", :path=>"logstash/inputs/azureblob", :error_message=>"no implicit conversion of nil into String", :error_class=>TypeError, :error_backtrace=>["org/jruby/RubyKernel.java:957:in `require'", "/usr/share/logstash/vendor/bundle/jruby/2.3.0/gems/polyglot-0.3.5/lib/polyglot.rb:65:in `require'", "/usr/share/logstash/vendor/bundle/jruby/2.3.0/gems/logstash-input-azureblob-0.9.13/lib/com/microsoft/json-parser.rb:3:in `'", "org/jruby/RubyKernel.java:955:in `...

Check the file com/microsoft/json-parser.rb:3
require Dir[ File.dirname(__FILE__) + "/../../*_jars.rb" ].first

Found there seems really no ../../*_jars.rb in the lib dir. Does the new plugin miss some file or we need install this file from some place? Thanks!