Add Prometheus and CopyArtifact plugins to Jenkins 2.71

Change-Id: I79849a402018ab88b45ee2ac655b67ecbf6b827f
diff --git a/Dockerfile b/Dockerfile
index 1588e43..4012177 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -81,6 +81,7 @@
         build-monitor-plugin \
         build-user-vars-plugin \
         categorized-view \
+        copyartifact \
         description-setter \
         discard-old-build \
         docker-workflow \
@@ -96,6 +97,7 @@
         monitoring \
         permissive-script-security \
         pipeline-utility-steps \
+        prometheus \
         rebuild \
         simple-theme-plugin \
         slack \