plugin fail if tags is not defined on config file

[egarbi]

According to documentation, default value for tags is "[]", and it is not required.
However, this error is coming if I don’t define tags on config file:

NoMethodError: undefined method `join' for nil:NilClass
  format_message at /opt/logstash/lib/logstash/outputs/s3.rb:351
         receive at /opt/logstash/lib/logstash/outputs/s3.rb:302
          handle at /opt/logstash/lib/logstash/outputs/base.rb:86
      initialize at (eval):41
            call at org/jruby/RubyProc.java:271
          output at /opt/logstash/lib/logstash/pipeline.rb:266
    outputworker at /opt/logstash/lib/logstash/pipeline.rb:225
   start_outputs at /opt/logstash/lib/logstash/pipeline.rb:152

[ph]

Thank you for reporting this bug, It will be fixed once this PR is merged
#1, this PR add initial support for supporting codecs for the output format. We have extracted the S3 format in the new s3_plain codec and fix the tag nil issue.

[ph]

Fixed in the latest mater, you need to use the https://github.com/logstash-plugins/logstash-codec-s3plain codec.

[egarbi]

Ok, thanks, Ill try