DATE column type not supported

[cm226]

Logstash information:

Please include the following information:

1. Logstash version

Using bundled JDK: /usr/share/logstash/jdk
logstash 8.12.1

Steps to reproduce:
Use the logstash input sqlLit plugin on a table with a DATE column

I used this plugin on a table with a DATE column type. It looks like the date column gets converted to a ruby date type and is passed on to logstash, which then doesn't know what to do with it.

Provide logs (if relevant):
The log message you get is this one:
Error: Missing Converter handling for full class name=org.jruby.gen.RubyObject31, simple name=RubyObject31

I tried to fix using the remove_field mutator, but it didn't seem to fix the issue, I'm not sure if the error is being generated before the mutator is being run?

I managed to fix it by adding

if element.instance_of? Date
                event.set(column.to_s, element.to_s)

To the plugin, I don't know much about ruby so there might be a better way. Ill raise a PR, in case this helps anybody else with the same issue.