Allow request parameter and proto file path

staging/src/k8s.io/code-generator/cmd/go-to-protobuf/protoc-gen-gogo/main.go

@@ -36,8 +36,12 @@ func main() {
 	// if we're given paths as inputs, generate .pb.go files based on those paths
 	for _, file := range request.FileToGenerate {
 		if strings.Contains(file, "/") {
+			if request.Parameter != nil {
+				*request.Parameter += ",paths=source_relative"
+			} else {
 				param := "paths=source_relative"
 				request.Parameter = &param
+			}
 			break
 		}
 	}