Update Docker image for dsv4-fp4-b200-vllm

Author: wzhao18

.github/configs/nvidia-master.yaml

@@ -1734,7 +1734,7 @@ dsv4-fp4-b200-sglang:
       - { tp: 8, ep: 8, dp-attn: true, conc-start: 256, conc-end: 512 }
 
 dsv4-fp4-b200-vllm:
-  image: vllm/vllm-openai:v0.20.2
+  image: vllm/vllm-openai:nightly-626fa9bba5663a5cf6a870debf031ee344ddb822
   model: deepseek-ai/DeepSeek-V4-Pro
   model-prefix: dsv4
   runner: b200-dsv4