Add "addObservableEvents" to initializeArchivable

[Kaylakaze]

So that the events fired by this trait can be handled properly in the model's observer, you need to add the following to the initializeArchivable method:
$this->addObservableEvents([ 'archiving', 'archived', 'unArchiving', 'unArchived' ]);

[joelbutcher]

Thanks for this - will take a look at some point later this week. If you have time yourself, please feel free to submit a PR!

[joelbutcher]

Resolved in v1.3.1