Update badge (#868)

Co-authored-by: Carson Hoffman <c@rsonhoffman.com>

README.md

@@ -1,6 +1,6 @@
 # DiscordGo
 
-[![GoDoc](https://godoc.org/github.com/bwmarrin/discordgo?status.svg)](https://godoc.org/github.com/bwmarrin/discordgo) [![Go report](http://goreportcard.com/badge/bwmarrin/discordgo)](http://goreportcard.com/report/bwmarrin/discordgo) [![Build Status](https://travis-ci.com/bwmarrin/discordgo.svg?branch=master)](https://travis-ci.com/bwmarrin/discordgo) [![Discord Gophers](https://img.shields.io/badge/Discord%20Gophers-%23discordgo-blue.svg)](https://discord.gg/0f1SbxBZjYoCtNPP) [![Discord API](https://img.shields.io/badge/Discord%20API-%23go_discordgo-blue.svg)](https://discord.com/invite/discord-api)
+[![Go Reference](https://pkg.go.dev/badge/github.com/bwmarrin/discordgo.svg)](https://pkg.go.dev/github.com/bwmarrin/discordgo) [![Go report](http://goreportcard.com/badge/bwmarrin/discordgo)](http://goreportcard.com/report/bwmarrin/discordgo) [![Build Status](https://travis-ci.com/bwmarrin/discordgo.svg?branch=master)](https://travis-ci.com/bwmarrin/discordgo) [![Discord Gophers](https://img.shields.io/badge/Discord%20Gophers-%23discordgo-blue.svg)](https://discord.gg/0f1SbxBZjYoCtNPP) [![Discord API](https://img.shields.io/badge/Discord%20API-%23go_discordgo-blue.svg)](https://discord.com/invite/discord-api)
 
 <img align="right" src="http://bwmarrin.github.io/discordgo/img/discordgo.png">
 
@@ -64,7 +64,7 @@ The DiscordGo code is fairly well documented at this point and is currently
 the only documentation available.  Both GoDoc and GoWalker (below) present
 that information in a nice format.
 
-- [![GoDoc](https://godoc.org/github.com/bwmarrin/discordgo?status.svg)](https://godoc.org/github.com/bwmarrin/discordgo) 
+- [![Go Reference](https://pkg.go.dev/badge/github.com/bwmarrin/discordgo.svg)](https://pkg.go.dev/github.com/bwmarrin/discordgo)
 - [![Go Walker](http://gowalker.org/api/v1/badge)](https://gowalker.org/github.com/bwmarrin/discordgo) 
 - Hand crafted documentation coming eventually.