Update dependencies. (#13778)

vendor/github.com/armon/go-metrics/go.mod

@@ -3,14 +3,17 @@ module github.com/armon/go-metrics
 go 1.12
 
 require (
-	github.com/DataDog/datadog-go v2.2.0+incompatible
+	github.com/DataDog/datadog-go v3.2.0+incompatible
 	github.com/circonus-labs/circonus-gometrics v2.3.1+incompatible
 	github.com/circonus-labs/circonusllhist v0.1.3 // indirect
+	github.com/golang/protobuf v1.2.0
 	github.com/hashicorp/go-immutable-radix v1.0.0
 	github.com/hashicorp/go-retryablehttp v0.5.3 // indirect
 	github.com/pascaldekloe/goe v0.1.0
 	github.com/pkg/errors v0.8.1 // indirect
 	github.com/prometheus/client_golang v0.9.2
+	github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910
+	github.com/prometheus/common v0.0.0-20181126121408-4724e9255275
 	github.com/stretchr/testify v1.3.0 // indirect
 	github.com/tv42/httpunix v0.0.0-20150427012821-b75d8614f926 // indirect
 )