Upgrade Prometheus to v2.7.1

- tested on GKE 1.11 and Istio 1.0.3

Signed-off-by: stefanprodan <[email protected]>

Author: stefanprodan

chart/openfaas/values.yaml

@@ -53,7 +53,7 @@ operator:
 
 # monitoring and auto-scaling components
 prometheus:
-  image: prom/prometheus:v2.6.1
+  image: prom/prometheus:v2.7.1
 alertmanager:
   image: prom/alertmanager:v0.15.0
 

yaml/prometheus-dep.yml

@@ -13,7 +13,7 @@ spec:
       serviceAccountName: openfaas-prometheus
       containers:
       - name: prometheus
-        image: prom/prometheus:v2.6.1
+        image: prom/prometheus:v2.7.1
         command:
           - "prometheus"
           - "--config.file=/etc/prometheus/prometheus.yml"