Use "Puma" instead of "puma" to reporting to New Relic

Current NEWRELIC_DISPACHER default value is not works
in Rails 4.2 with Puma, New Relic on Heroku.

Not works:

    $ heroku config:add NEWRELIC_DISPACHER=puma

Works:

    $ heroku config:add NEWRELIC_DISPACHER=Puma

So I have updated default value.

lib/puma/cli.rb

@@ -35,7 +35,7 @@ module Puma
 
       @config = nil
 
-      ENV['NEWRELIC_DISPATCHER'] ||= "puma"
+      ENV['NEWRELIC_DISPATCHER'] ||= "Puma"
 
       setup_options
       generate_restart_data