Update protoc-gen-grpc-gateway/gengateway/template.go
Update protoc-gen-grpc-gateway/gengateway/template.go

Co-Authored-By: Johan Brandhorst <8c98250619a5229afaab52d25e022b9e3e1d22a2@gmail.com>
improbable-io/grpc-gateway,improbable-io/grpc-gateway,gengo/grpc-gateway,gengo/grpc-gateway,grpc-ecosystem/grpc-gateway