add enum support

[ariaieboy]

this PR fixes #11
after this PR Users can pass the enum case name to the $dispatchesEvent.

[ariaieboy]

cc: @jpkleemans

[jpkleemans]

Thanks for your PR! I've added your work into v1.4.0

[radmen]

@jpkleemans I just had the chance to use the latest package version with the fix @ariaieboy created.

I have one question for you folks. Should we use the enum name or the value to trigger the event?

My gut feeling was to use something like this:

protected $dispatchesEvents = [
    'status:confirmed' => Event::class,
];

I thought this is the correct definition because the value stored in the DB will be confirmed. I had to use CONFIRMED because this is the name of the enum case representing that value.

[radmen]

Hmm, I think the above is fixed in #16.