Adds Prometheus go vendor to mod

Signed-off-by: JoshVanL <vleeuwenjoshua@gmail.com>

Author: JoshVanL

go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/heptiolabs/healthcheck v0.0.0-20180807145615-6ff867650f40
 	github.com/onsi/ginkgo v1.11.0
 	github.com/onsi/gomega v1.7.0
+	github.com/prometheus/client_golang v1.0.0
 	github.com/sebest/xff v0.0.0-20160910043805-6c115e0ffa35
 	github.com/sirupsen/logrus v1.4.2
 	github.com/spf13/cobra v0.0.5