Fix Python 3.8 compatibility for idp_attributes type

Use Dict[str, Any] instead of dict[str, Any] for Python 3.8 compatibility.
The lowercase dict syntax is only available in Python 3.9+.

Fixes issue identified by Greptile bot review.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: ajworkos

src/workos/types/user_management/organization_membership.py

@@ -1,4 +1,4 @@
-from typing import Any, Literal, Sequence, Optional
+from typing import Any, Dict, Literal, Sequence, Optional
 from typing_extensions import TypedDict
 
 from workos.types.workos_model import WorkOSModel
@@ -21,6 +21,6 @@ class OrganizationMembership(WorkOSModel):
     role: OrganizationMembershipRole
     roles: Optional[Sequence[OrganizationMembershipRole]] = None
     status: LiteralOrUntyped[OrganizationMembershipStatus]
-    idp_attributes: dict[str, Any]
+    idp_attributes: Dict[str, Any]
     created_at: str
     updated_at: str