Added `artisan:bugsnag:deploy` task

[andrecolza]

Added task to notify BugSnag of releases using the Laravel Artisan console.

• [ ] Bug fix #…?

• [x] New feature?

• [ ] BC breaks?

• [ ] Tests added?

• [x] Docs added?

  Please, regenerate docs by running next command:
  $ php bin/docgen
  

BugSnag provides a Laravel Artisan bugsnag:deploy command to report releases. This PR adds a task in contrib/bugsnag.php to allow use that command when deploying.

Note: I required the Laravel recipe to allow the use of artisan function, not sure if is the right way.

This is related to #3402

[antonmedv]

Let’s put in the laravel recipe.

[andrecolza]

@antonmedv Ok, I can open a second PR to put the new task it in the Laravel recipe, but I think it shouldn't be placed there: the Laravel recipe only contains tasks related to first-party commands, while this is a command provided by a third-party package (BugSnag).

The only other case I've found in Deployer is about Statamic, which has its own recipe that extends the Laravel recipe. Are you sure you prefer this task to be added in the Laravel recipe?

[antonmedv]

Definitely not importing laravel in contrib.