Merge pull request #32 from jeffreyvanhees/patch-4

Contact's lastname should be nullable

Author: sandervanhooft

src/Api/Contacts/Contact.php

@@ -14,7 +14,7 @@ class Contact extends BaseDto
 
     public ?string $firstname;
 
-    public string $lastname;
+    public ?string $lastname;
 
     public ?string $address1;