set default_codec doc attribute

Author: jsvd

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 3.1.4
+  - Docs: Set the default_codec doc attribute.
+
 ## 3.1.3
   - Update gemspec summary
 

docs/index.asciidoc

@@ -1,5 +1,6 @@
 :plugin: mongodb
 :type: output
+:default_codec: plain
 
 ///////////////////////////////////////////
 START - GENERATED VARIABLES, DO NOT EDIT!
@@ -131,4 +132,6 @@ See http://docs.mongodb.org/manual/reference/connection-string/.
 
 
 [id="plugins-{type}s-{plugin}-common-options"]
-include::{include_path}/{type}.asciidoc[]
+include::{include_path}/{type}.asciidoc[]
+
+:default_codec!:

logstash-output-mongodb.gemspec

@@ -1,6 +1,6 @@
 Gem::Specification.new do |s|
   s.name            = 'logstash-output-mongodb'
-  s.version         = '3.1.3'
+  s.version         = '3.1.4'
   s.licenses        = ['Apache License (2.0)']
   s.summary         = "Writes events to MongoDB"
   s.description     = "This gem is a Logstash plugin required to be installed on top of the Logstash core pipeline using $LS_HOME/bin/logstash-plugin install gemname. This gem is not a stand-alone program"