fix(docs): typo in helm install instructions (#11141)

Signed-off-by: Ramon Ziai <ramon.ziai@bettermarks.com>

docs/source/serving/deploying_with_helm.rst

@@ -25,7 +25,7 @@ To install the chart with the release name ``test-vllm``:
 
 .. code-block:: console
 
-    helm upgrade --install --create-namespace --namespace=ns-vllm test-vllm . -f values.yaml --set secrets.s3endpoint=$ACCESS_POINT --set secrets.s3buckername=$BUCKET --set secrets.s3accesskeyid=$ACCESS_KEY --set secrets.s3accesskey=$SECRET_KEY
+    helm upgrade --install --create-namespace --namespace=ns-vllm test-vllm . -f values.yaml --set secrets.s3endpoint=$ACCESS_POINT --set secrets.s3bucketname=$BUCKET --set secrets.s3accesskeyid=$ACCESS_KEY --set secrets.s3accesskey=$SECRET_KEY
 
 Uninstalling the Chart
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