I would like to add async engine name

[saiqulhaq]

Hi Rollbar team

My team doesn't know that our Rollbar config uses Sidekiq for reporting, and the Sidekiq was not running on that time
he was wondering why the report is not available on Rollbar
so would you accept my PR if I add any async engine name into the following notifier class?

rollbar-gem/lib/rollbar/notifier.rb

Line 905 in 9efecb9

"[Rollbar] Details: #{uuid_url} (only available if report was successful)"

[waltjones]

@saiqulhaq Sounds like you'd just add the async engine name to the log string, if present? Yes, that would be an acceptable change, assuming the implementation doesn't have side effects.