Update common Prometheus files (#648)

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

Author: prombot

.circleci/config.yml

@@ -4,8 +4,7 @@ jobs:
     working_directory: ~/circleci-java
     docker:
       - image: circleci/openjdk:8-jdk-stretch
-
-    steps: 
+    steps:
       - checkout
       - restore_cache: # restore the saved cache after the first run or if `pom.xml` has changed
           key: circleci-demo-java-spring-{{ checksum "pom.xml" }}
@@ -14,5 +13,6 @@ jobs:
           paths:
             - ~/.m2
           key: circleci-demo-java-spring-{{ checksum "pom.xml" }}
-      
       - run: mvn package
+orbs:
+  prometheus: prometheus/[email protected]