Examples use subdue when they shouldn't

[asachs01]

subdue isn't a valid attribute in Sensu Go as of yet, but the examples in the Cookbook reference subdue in multiple places. They should be corrected to have subdue removed.

[majormoses]

I think that must have been a quick mistake since the sensu ruby did support it and it was present in the list. Agree we should remove it until its actually implemented.