[11.x] Adds finally method to pipeline helper

[nunomaduro]

This pull request adds the finally method to pipeline helper, so we can specify a callback to be executed regardless of the outcome of the pipeline.

This is the before:

try {
    $result = Pipeline::send($deployment)
        ->through([PipeOne::class, PipeTwo::class]) // one of the pipes does not call the $next or throws an exception...
        ->then(fn () => $deployment->deploy());
} finally {
    // perform clean up...
}

This is the after:

$result = Pipeline::send($deployment)
     ->through([PipeOne::class, PipeTwo::class]) // one of the pipes does not call the $next or throws an exception...
     ->finally(fn () => /** perform clean up */)
     ->then(fn () => $deployment->deploy());

[parijke]

Shouldn't the finally method be declared in https://github.com/laravel/framework/blob/11.x/src%2FIlluminate%2FSupport%2FFacades%2FPipeline.php as well?

[taylorotwell]

@parijke our facades are updated automatically by a script.

[parijke]

@parijke our facades are updated automatically by a script.

That is cool @taylorotwell wow!