Add opentelemetry & update gRPC (#41)

* add opentelemetry & upgrade grpc code

Warning: this commit updates the grpc version and this might break
downstream builds could be impacted after a `go mod tidy`.

Adds otel hooks to the gRPC server helper and as a side-effect, updates
gRPC and protocol buffers on the way.

* update docs to say otel interceptors are now on by default

Signed-off-by: Amy Tobey <atobey@equinix.com>

Author: Amy Tobey

go.mod

@@ -4,23 +4,21 @@ go 1.12
 
 require (
 	github.com/gogo/protobuf v1.2.1 // indirect
-	github.com/golang/protobuf v1.3.2 // indirect
 	github.com/grpc-ecosystem/go-grpc-middleware v1.0.0
 	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0
 	github.com/konsorten/go-windows-terminal-sequences v1.0.2 // indirect
 	github.com/pkg/errors v0.9.1
 	github.com/prometheus/client_golang v1.0.0
-	github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90
+	github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4
 	github.com/prometheus/common v0.6.0 // indirect
 	github.com/prometheus/procfs v0.0.3 // indirect
 	github.com/rollbar/rollbar-go v1.0.2
 	github.com/sirupsen/logrus v1.4.2 // indirect
-	github.com/stretchr/testify v1.6.1
+	github.com/stretchr/testify v1.7.0
+	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.22.0
 	go.uber.org/multierr v1.6.0 // indirect
 	go.uber.org/zap v1.16.0
-	golang.org/x/net v0.0.0-20190628185345-da137c7871d7 // indirect
-	golang.org/x/sys v0.0.0-20190712062909-fae7ac547cb7 // indirect
 	golang.org/x/text v0.3.2 // indirect
-	google.golang.org/genproto v0.0.0-20190708153700-3bdd9d9f5532 // indirect
-	google.golang.org/grpc v1.22.0
+	google.golang.org/grpc v1.39.0
+	google.golang.org/grpc/examples v0.0.0-20210728214646-ad0a2a847cdf
 )