[DOC] Reorder configuration options and bump to v3.5.1 (logstash-plug…

…ins#79)

* Reorder options

* Bump to v3.5.1

* Update CHANGELOG.md

Update README.md

Merge pull request logstash-plugins#71 from karenzone/70-datatype

Correct data_type label in docs

fix broken tests on renaming feature

set default_codec doc attribute

bump to 3.2.0

[skip ci] update gemspec summary

Pin redis dep to 3.x.x since 4.x requires ruby 2+ syntax

Fixes logstash-plugins#59

Version bump

For elastic/logstash#7993

[ci skip]

bump patch level for doc generation