Test: adjust for devutils 2.0 compat

Author: kares

logstash-output-file.gemspec

@@ -25,6 +25,7 @@ Gem::Specification.new do |s|
  s.add_runtime_dependency 'logstash-codec-line'
 
  s.add_development_dependency 'logstash-devutils'
+ s.add_development_dependency 'insist'
  s.add_development_dependency 'flores'
  s.add_development_dependency 'logstash-input-generator'
 end

spec/outputs/file_spec.rb

@@ -1,5 +1,6 @@
 # encoding: UTF-8
 require "logstash/devutils/rspec/spec_helper"
+require "insist"
 require "logstash/outputs/file"
 require "logstash/codecs/line"
 require "logstash/codecs/json_lines"