minor type fix

src/ApiResources/Organization/OrganizationCreationRequest.php

@@ -359,12 +359,12 @@ class OrganizationCreationRequest
         return $this;
     }
 
-    public function getPrincipalType(): PrincipalTypeEnum
+    public function getPrincipalType(): ?PrincipalTypeEnum
     {
         return $this->principalType;
     }
 
-    public function setPrincipalType(PrincipalTypeEnum $principalType): self
+    public function setPrincipalType(?PrincipalTypeEnum $principalType): self
     {
         $this->principalType = $principalType;