[Test Failure] ECS compatibility enabled tests are failing on Logstash 8.x

[robbavey]

https://app.travis-ci.com/github/logstash-plugins/logstash-input-stdin/jobs/572876533

logstash_1_2c9e893a812c |   ECS behavior
logstash_1_2c9e893a812c |     `ecs_compatibility => v8`
logstash_1_2c9e893a812c |       sets hostname
logstash_1_2c9e893a812c |       sets event.original (FAILED - 1)
logstash_1_2c9e893a812c |       sets message
logstash_1_2c9e893a812c |     `ecs_compatibility => v1`
logstash_1_2c9e893a812c |       sets hostname
logstash_1_2c9e893a812c |       sets message
logstash_1_2c9e893a812c |       sets event.original (FAILED - 2)
logstash_1_2c9e893a812c | 
logstash_1_2c9e893a812c | Failures:
logstash_1_2c9e893a812c | 
logstash_1_2c9e893a812c |   1) LogStash::Inputs::Stdin ECS behavior `ecs_compatibility => v8` sets event.original
logstash_1_2c9e893a812c |      Failure/Error: expect( event.get('event') ).to eql 'original' => stdin_data
logstash_1_2c9e893a812c |      
logstash_1_2c9e893a812c |        expected: {"original"=>"a foo bar\n"}
logstash_1_2c9e893a812c |             got: {"original"=>"a foo bar"}
logstash_1_2c9e893a812c |      
logstash_1_2c9e893a812c |        (compared using eql?)
logstash_1_2c9e893a812c |      
logstash_1_2c9e893a812c |        Diff:
logstash_1_2c9e893a812c |        @@ -1 +1 @@
logstash_1_2c9e893a812c |        -"original" => "a foo bar\n",
logstash_1_2c9e893a812c |        +"original" => "a foo bar",
logstash_1_2c9e893a812c |        
logstash_1_2c9e893a812c |      # ./spec/inputs/stdin_spec.rb:67:in `block in /usr/share/plugins/plugin/spec/inputs/stdin_spec.rb'
logstash_1_2c9e893a812c | 
logstash_1_2c9e893a812c |   2) LogStash::Inputs::Stdin ECS behavior `ecs_compatibility => v1` sets event.original
logstash_1_2c9e893a812c |      Failure/Error: expect( event.get('event') ).to eql 'original' => stdin_data
logstash_1_2c9e893a812c |      
logstash_1_2c9e893a812c |        expected: {"original"=>"a foo bar\n"}
logstash_1_2c9e893a812c |             got: {"original"=>"a foo bar"}
logstash_1_2c9e893a812c |      
logstash_1_2c9e893a812c |        (compared using eql?)
logstash_1_2c9e893a812c |      
logstash_1_2c9e893a812c |        Diff:
logstash_1_2c9e893a812c |        @@ -1 +1 @@
logstash_1_2c9e893a812c |        -"original" => "a foo bar\n",
logstash_1_2c9e893a812c |        +"original" => "a foo bar",
logstash_1_2c9e893a812c |        
logstash_1_2c9e893a812c |      # ./spec/inputs/stdin_spec.rb:67:in `block in <main>'
logstash_1_2c9e893a812c | 
logstash_1_2c9e893a812c | Finished in 5.21 seconds (files took 13.84 seconds to load)
logstash_1_2c9e893a812c | 11 examples, 2 failures
logstash_1_2c9e893a812c | 
logstash_1_2c9e893a812c | Failed examples:
logstash_1_2c9e893a812c | 
logstash_1_2c9e893a812c | rspec './spec/inputs/stdin_spec.rb[1:3:2:3]' # LogStash::Inputs::Stdin ECS behavior `ecs_compatibility => v8` sets event.original
logstash_1_2c9e893a812c | rspec './spec/inputs/stdin_spec.rb[1:3:1:3]' # LogStash::Inputs::Stdin ECS behavior `ecs_compatibility => v1` sets event.original
logstash_1_2c9e893a812c | 
logstash_1_2c9e893a812c | Randomized with seed 62919
logstash_1_2c9e893a812c | 
ci_logstash_1_2c9e893a812c exited with code 1