Fix typo in job name for k8s services in prometheus.yml

Right wording is:

    job_name: 'kubernetes-service-endpoints'

E.g., see https://github.com/prometheus/prometheus/blob/14d0604aba95c7bb434f3a7687f7903bbe4fd81f/documentation/examples/prometheus-kubernetes.yml#L97

Change-Id: I997ffc96b1ab6b81e2e634d0be48ad73daf2f077
diff --git a/prometheus/files/prometheus.yml b/prometheus/files/prometheus.yml
index 0164cdd..69bc0f6 100644
--- a/prometheus/files/prometheus.yml
+++ b/prometheus/files/prometheus.yml
@@ -111,7 +111,7 @@
       regex: __meta_kubernetes_node_label_(.+)
 
 
-  - job_name: 'kubernetes-service-endpoint'
+  - job_name: 'kubernetes-service-endpoints'
     scheme: https
     tls_config:
       insecure_skip_verify: true