Increase sliding window to 5hr for request_latencies metric

Kubernetes-commit: e1ba3da16c9bebccb3902952d56b59f2e2dbb900

pkg/endpoints/metrics/metrics.go

@@ -56,8 +56,9 @@ var (
 		prometheus.SummaryOpts{
 			Name: "apiserver_request_latencies_summary",
 			Help: "Response latency summary in microseconds for each verb, resource and subresource.",
-			// Make the sliding window of 1h.
-			MaxAge: time.Hour,
+			// Make the sliding window of 5h.
+			// TODO: The value for this should be based on our SLI definition (medium term).
+			MaxAge: 5 * time.Hour,
 		},
 		[]string{"verb", "resource", "subresource", "scope"},
 	)