Bump google.golang.org/grpc from 1.37.0 to 1.56.3

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.37.0 to 1.56.3.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](grpc/grpc-go@v1.37.0...v1.56.3)

---
updated-dependencies:
- dependency-name: google.golang.org/grpc
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

go.mod

@@ -4,13 +4,13 @@ go 1.13
 
 require (
 	github.com/Netflix/spectator-go v0.1.3
-	github.com/cespare/xxhash/v2 v2.1.1
+	github.com/cespare/xxhash/v2 v2.2.0
 	github.com/frankban/quicktest v1.11.1 // indirect
 	github.com/go-zookeeper/zk v1.0.2
-	github.com/golang/mock v1.4.3
-	github.com/golang/protobuf v1.4.2
+	github.com/golang/mock v1.6.0
+	github.com/golang/protobuf v1.5.3
 	github.com/google/gnxi v0.0.0-20200831120455-017df4756f78
-	github.com/google/go-cmp v0.5.2
+	github.com/google/go-cmp v0.5.9
 	github.com/influxdata/influxdb-client-go/v2 v2.2.3
 	github.com/kelseyhightower/envconfig v1.4.0
 	github.com/netbox-community/go-netbox v0.0.0-20201002085217-91e5d561efe4
@@ -19,11 +19,8 @@ require (
 	github.com/prometheus/client_golang v1.4.1
 	github.com/rs/zerolog v1.17.2
 	github.com/segmentio/kafka-go v0.4.6
-	github.com/stretchr/testify v1.6.1
-	golang.org/x/net v0.0.0-20201021035429-f5854403a974 // indirect
-	golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9
-	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
-	google.golang.org/grpc v1.37.0
-	google.golang.org/protobuf v1.25.1-0.20200805231151-a709e31e5d12 // indirect
+	github.com/stretchr/testify v1.8.3
+	golang.org/x/sync v0.1.0
+	google.golang.org/grpc v1.56.3
 	gopkg.in/yaml.v2 v2.3.0
 )