Update common Prometheus files (#730)

Signed-off-by: prombot <prometheus-team@googlegroups.com>

Author: prombot

.circleci/config.yml

@@ -17,4 +17,4 @@ jobs:
             - ~/.m2
           key: maven-dependencies-{{ checksum "pom.xml" }}
 orbs:
-  prometheus: prometheus/prometheus@0.14.0
+  prometheus: prometheus/prometheus@0.15.0