$this->app->share deprecated in 5.4

[whoacowboy]

Couldn't figure out the pull request.

https://github.com/maknz/slack/blob/1.7.0/src/SlackServiceProviderLaravel5.php#L27

Change

$this->app['maknz.slack'] = $this->app->share(function($app)

to

$this->app->singleton('maknz.slack', function($app)

[AlexDanault]

@maknz said on twitter that he doesn't have time to maintain this package anymore and will soon post a deprecation notice.

Link: https://twitter.com/maknz/status/833866298232754177