set default_codec doc attribute 

[skip ci] update gemspec summary 

Version bump For elastic/logstash#7993 [ci skip]

remove obsolete option data_timeout 

bump patch level for doc generation 

Update CHANGELOG.md 

Limit objects accepted to be only log4j objects Fixes #39

missing is 

dependency logstash-core-plugin-api >= 1.60 <= 2.99 

Make sure all the gems were published under jruby