feat: add Organization Member, Role, and Invitation management

[fern-api]

Changes

SDK regeneration from the Auth0 OpenAPI spec via Fern. Adds Member
Management to the My Organization API - organization members, member
role assignment, member invitations, bulk membership deletion, and
organization roles. This is the final beta before the stable 1.0.0
release, so the type renames below are landed now, ahead of the
compatibility commitment.

🆕 New endpoints / types:

• Members - client.organization.members.list() and .get(user_id) (GET members, GET members/{user_id}), with ListOrganizationMembersResponseContent and OrgMemberId
• Member Roles - client.organization.members.roles.list/assign/unassign (GET/POST/DELETE members/{user_id}/roles), with GetOrganizationMemberRolesResponseContent and OrganizationMemberRolesChangeRequestContent
• Member Invitations - client.organization.invitations.list/create/get/delete (GET/POST member-invitations, GET/DELETE member-invitations/{id}), with CreateMemberInvitationInvitee, CreateMemberInvitationResponseContent, and ListMembersInvitationsResponseContent
• Memberships - client.organization.memberships.delete_memberships() (POST delete-memberships)
• Organization Roles - client.organization.roles.list() (GET roles), with Role, RoleId, and ListRolesResponseContent

✏️ Modified types:

• phone_number added to OrgMember

Renamed / removed (beta):

• Renamed OrgMemberRole -> Role and OrgMemberRoleId -> RoleId; OrgMember.roles and MemberInvitation.roles now use the renamed types. These were exported type names with no shipped endpoint behind them.
• Removed delete:my_org:members and update:my_org:member_roles from the OAuthScope enum.

Chores / CI

• Dropped Python 3.9 (minimum is now 3.10). The unpinned poetry install in CI fails on 3.9 because a current poetry dependency uses dataclass(slots=...), which only exists on 3.10+.
• Bumped dev dependencies: mypy, requests, types-requests, types-python-dateutil, pytest-xdist.