protoc-gen-go uses deprecated libraries

[bsr]

Hello,

I am coming back to a project after few months, and there has been changes to the protobuf libraries. I read the blog post, and docs followed the instructions to install and use the library. Please see the below header of the generated code.

I uses the latest library version, but it still include older versions. I was expecting

github.com/golang/protobuf/proto ->

google.golang.org/protobuf/proto

github.com/golang/protobuf/ptypes/timestamp ->

google.golang.org/protobuf/types/known/timestamppb

etc.

what am I missing?

```

// Code generated by protoc-gen-go. DO NOT EDIT.

// versions:

// protoc-gen-go v1.25.0

// protoc v3.13.0

// source: v1/beat/xyz/test.proto

package xyz

import (

proto "github.com/golang/protobuf/proto"

timestamp "github.com/golang/protobuf/ptypes/timestamp"

protoreflect "google.golang.org/protobuf/reflect/protoreflect"

protoimpl "google.golang.org/protobuf/runtime/protoimpl"

reflect "reflect"

sync "sync"

)

```