Fixed getSuppressions return type (#126)

Fixed getSuppressions to return PostmarkSuppressionList instead of
PostmarkSuppressionResultList

Author: ashgibson

src/Postmark/PostmarkClient.php

@@ -35,6 +35,7 @@
 use Postmark\Models\Stats\PostmarkOutboundSentStats;
 use Postmark\Models\Stats\PostmarkOutboundSpamComplaintStats;
 use Postmark\Models\Stats\PostmarkOutboundTrackedStats;
+use Postmark\Models\Suppressions\PostmarkSuppressionList;
 use Postmark\Models\Suppressions\PostmarkSuppressionResultList;
 use Postmark\Models\TemplatedPostmarkMessage;
 use Postmark\Models\TemplateValidationResponse;
@@ -1473,7 +1474,7 @@ public function getSuppressions(
         ?string $fromDate = null,
         ?string $toDate = null,
         ?string $emailAddress = null
-    ): PostmarkSuppressionResultList {
+    ): PostmarkSuppressionList {
         $query = [];
         $query['SuppressionReason'] = $suppressionReason;
         $query['Origin'] = $origin;
@@ -1485,7 +1486,7 @@ public function getSuppressions(
             $messageStream = 'outbound';
         }
 
-        return new PostmarkSuppressionResultList((array) $this->processRestRequest('GET', "/message-streams/{$messageStream}/suppressions/dump", $query));
+        return new PostmarkSuppressionList((array) $this->processRestRequest('GET', "/message-streams/{$messageStream}/suppressions/dump", $query));
     }
 
     /**