internal/compression/grpc: use import block for blank import (#402)
internal/compression/grpc: use import block for blank import (#402)

Just encountered https://github.com/golang/lint/issues/366
whose work around is to convert a single blank import "_"
into a block import.
open-telemetry/opentelemetry-collector,open-telemetry/opentelemetry-collector-contrib,open-telemetry/opentelemetry-collector,open-telemetry/opentelemetry-collector,census-instrumentation/opencensus-service,census-instrumentation/opencensus-service,open-telemetry/opentelemetry-collector-contrib