set default_codec doc attribute 

version bump for 3.0.6 patch release Fixes #23

[skip ci] update gemspec summary 

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

bump patch level for doc generation 

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

Make sure all the gems were published under jruby 

version 3.0.0 

dependency logstash-core-plugin-api ~> 1.0 

dependency logstash-core > 2.0.0 < 6.0.0.alpha1