[Chore] Bump Python version and apply formatting changes for v0.12 release (#126)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

vllm_omni/diffusion/data.py

@@ -4,8 +4,9 @@
 import enum
 import os
 import random
+from collections.abc import Callable
 from dataclasses import dataclass, field, fields
-from typing import Any, Callable
+from typing import Any
 
 import torch
 from vllm.logger import init_logger