Pass along new polling_opts

[benonymus]

The newly added opts for Polling.build/5 are not passed from the Oban plugin when called like so:

{Plugins.Oban, oban_supervisors: [Oban], poll_rate: 10_000, opts: [detach_on_error: false]}

#236
3feeceb

[coveralls]

coverage: 76.954% (-0.2%) from 77.131%
when pulling 56c19c4 on benonymus:master
into 6f97943 on akoutmos:master.

[akoutmos]

Good catch! Thanks for the fix.

[smn]

@akoutmos any chance a new release could be made to include this?