Adapt vLLM requirements changes to fix main CI (#279)

### What this PR does / why we need it?
Adapt vLLM requirements changes:
206e2577fa (diff-01ec17406c969585ed075609a2bbf2f2f4fe3e3def36946694abe6d4eb60a6f2)

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?
CI passed

Signed-off-by: Yikun Jiang <yikunkero@gmail.com>

docs/source/developer_guide/contributing.md

@@ -21,7 +21,7 @@ source ./.venv/bin/activate
 # Clone vllm code and install
 git clone https://github.com/vllm-project/vllm.git
 cd vllm
-pip install -r requirements-build.txt
+pip install -r requirements/build.txt
 VLLM_TARGET_DEVICE="empty" pip install .
 cd ..
 

docs/source/developer_guide/contributing.zh.md

@@ -17,7 +17,7 @@ source ./.venv/bin/activate
 # 克隆并安装vllm
 git clone https://github.com/vllm-project/vllm.git
 cd vllm
-pip install -r requirements-build.txt
+pip install -r requirements/build.txt
 VLLM_TARGET_DEVICE="empty" pip install .
 cd ..