[Doc] Update pytorch version in README_zh doc (vllm-project#2202)

### What this PR does / why we need it?

Update pytorch version in README_zh doc.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

Local Test.
- vLLM version: v0.10.0
- vLLM main:
vllm-project/vllm@bd3db7f

Signed-off-by: xleoken <xleoken@163.com>

Author: xleoken

README.zh.md

@@ -42,7 +42,7 @@ vLLM 昇腾插件 (`vllm-ascend`) 是一个由社区维护的让vLLM在Ascend NP
 - 软件：
   * Python >= 3.9, < 3.12
   * CANN >= 8.2.rc1
-  * PyTorch >= 2.5.1, torch-npu >= 2.7.1.dev20250724
+  * PyTorch >= 2.7.1, torch-npu >= 2.7.1.dev20250724
   * vLLM (与vllm-ascend版本一致)
 
 ## 开始使用