Add random associations for Artist -> Label in seeded data

[poppabear8883]

As the title suggests, we are missing this piece of data to be able to test this relationship properly

[cbj4074]

This is possible using the Factory State:

https://github.com/indiehd/web-api/blob/master/database/factories/ArtistFactory.php#L11

For example:

$ php artisan tinker
Psy Shell v0.9.7 (PHP 7.2.9-1+ubuntu18.04.1+deb.sury.org+1 — cli) by Justin Hileman
>>> factory(\App\Artist::class)->states('onLabel')->create();
=> App\Artist {#2955
     label_id: 38,
     updated_at: "2018-09-13 23:06:38",
     created_at: "2018-09-13 23:06:38",
     id: 88,
   }
>>> \App\Artist::find(88)->label;
=> App\Label {#2925
     id: 38,
     created_at: "2018-09-13 23:06:38",
     updated_at: "2018-09-13 23:06:38",
   }

Will that satisfy the need at hand?

[poppabear8883]

For now it solves what I was currently working on, but this issue still needs addressed as we discussed on discord:

the issue is that when you run --seed these associations are not there
so we need to make it where we can add a number of artists to random labels just for dummy data