Bump google.golang.org/grpc in /example/prom-collector (#1620)

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.35.0 to 1.36.0.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](grpc/grpc-go@v1.35.0...v1.36.0)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

example/prom-collector/go.mod

@@ -16,7 +16,7 @@ require (
 	go.opentelemetry.io/otel/metric v0.17.0
 	go.opentelemetry.io/otel/sdk v0.17.0
 	go.opentelemetry.io/otel/sdk/metric v0.17.0
-	google.golang.org/grpc v1.35.0
+	google.golang.org/grpc v1.36.0
 )
 
 replace go.opentelemetry.io/otel/bridge/opencensus => ../../bridge/opencensus

example/prom-collector/go.sum

@@ -408,6 +408,8 @@ google.golang.org/grpc v1.26.0/go.mod h1:qbnxyOmOxrQa7FizSgH+ReBfzJrCY1pSN7KXBS8
 google.golang.org/grpc v1.27.0/go.mod h1:qbnxyOmOxrQa7FizSgH+ReBfzJrCY1pSN7KXBS8abTk=
 google.golang.org/grpc v1.35.0 h1:TwIQcH3es+MojMVojxxfQ3l3OF2KzlRxML2xZq0kRo8=
 google.golang.org/grpc v1.35.0/go.mod h1:qjiiYl8FncCW8feJPdyg3v6XW24KsRHe+dy9BAGRRjU=
+google.golang.org/grpc v1.36.0 h1:o1bcQ6imQMIOpdrO3SWf2z5RV72WbDwdXuK0MDlc8As=
+google.golang.org/grpc v1.36.0/go.mod h1:qjiiYl8FncCW8feJPdyg3v6XW24KsRHe+dy9BAGRRjU=
 google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
 google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=
 google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQJ+fmap5saPgwCLgHXTUD7jkjRqWcaiX5VyM=