Update the broken link related to vllm metrics (#1574)

Signed-off-by: Emre ATAKLI <[email protected]>

Author: atakli

docs/source/features/autoscaling/metric-based-autoscaling.rst

@@ -27,7 +27,7 @@ While HPA and KPA are widely used, they are not specifically designed and optimi
 Metrics
 -------
 
-AiBrix supports all the vllm metrics. Please refer to https://docs.vllm.ai/en/stable/serving/metrics.html
+AiBrix supports all the vllm metrics. Please refer to https://docs.vllm.ai/en/stable/design/metrics.html
 
 How to deploy autoscaling policy
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