[stable/prometheus] add livenessProbe and readinessProbe (#3042)

Use /-/healthy for livenessProbe and /-/ready for readinessProbe
Fix #3000

stable/prometheus/Chart.yaml

@@ -1,5 +1,5 @@
 name: prometheus
-version: 5.0.0
+version: 5.0.1
 description: Prometheus is a monitoring system and time series database.
 home: https://prometheus.io/
 icon: https://raw.githubusercontent.com/prometheus/prometheus.github.io/master/assets/prometheus_logo-cb55bb5c346.png

stable/prometheus/templates/server-deployment.yaml

@@ -71,7 +71,13 @@ spec:
             - containerPort: 9090
           readinessProbe:
             httpGet:
-              path: {{ .Values.server.prefixURL }}/status
+              path: /-/ready
+              port: 9090
+            initialDelaySeconds: 30
+            timeoutSeconds: 30
+          livenessProbe:
+            httpGet:
+              path: /-/healthy
               port: 9090
             initialDelaySeconds: 30
             timeoutSeconds: 30