VOL-2496 Add "event listen" command to voltctl

Change-Id: I8f1fb34b55f56c8125142ac289e2f19fc170d804
diff --git a/go.mod b/go.mod
index 7b70d1b..5ce9c07 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,7 @@
 go 1.12
 
 require (
+	github.com/Shopify/sarama v1.25.0
 	github.com/fullstorydev/grpcurl v1.4.0
 	github.com/gogo/protobuf v1.2.1 // indirect
 	github.com/golang/protobuf v1.3.1