Update values.yaml (#96)

there is no health check in default image tag(1.7.0) in helm values.yaml

Author: ctrlxx

helm/prometheus-kafka-adapter/values.yaml

@@ -6,7 +6,7 @@ replicaCount: 1
 
 image:
   repository: telefonica/prometheus-kafka-adapter
-  tag: 1.7.0
+  tag: 1.8.0
   pullPolicy: IfNotPresent
 
 imagePullSecrets: []