Pending tenants refactor (BC break)

- [BC BREAK] Make pullPendingFromPool() $firstOrCreate arg
  default to false (pullPending() is now a direct alias for
  pullPendingFromPool() with default $firstOrCreate=true)
- Resolve race conditions in pullPendingFromPool()
- Make createPending() set pending_since regardless of exceptions
- Make pullPending() accept $attributes
- Fire PullingPendingTenant from within a DB transaction
- Clarify --count arg description for CreatePendingTenants command
- Add docblock to PullingPendingTenant with a notice

src/Events/PullingPendingTenant.php

@@ -4,4 +4,9 @@ declare(strict_types=1);
 
 namespace Stancl\Tenancy\Events;
 
+/**
+ * Importantly, listeners for this event should not switch tenancy context.
+ *
+ * This event is fired from within a database transaction.
+ */
 class PullingPendingTenant extends Contracts\TenantEvent {}