update doc url from godoc to pkg.go.dev

Signed-off-by: Amal Alkhamees <amalkms5@gmail.com>

README.md

@@ -2,7 +2,7 @@
 
 [![Go Report Card](https://goreportcard.com/badge/github.com/openfaas/faas)](https://goreportcard.com/report/github.com/openfaas/faas)
 [![Build Status](https://travis-ci.com/openfaas/faas.svg?branch=master)](https://travis-ci.com/openfaas/faas)
-[![GoDoc](https://godoc.org/github.com/openfaas/faas?status.svg)](https://godoc.org/github.com/openfaas/faas)
+[![go.dev reference](https://img.shields.io/badge/go.dev-reference-007d9c?logo=go&logoColor=white&style=flat-square)](https://pkg.go.dev/github.com/openfaas/faas)
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 [![OpenFaaS](https://img.shields.io/badge/openfaas-serverless-blue.svg)](https://www.openfaas.com)
 [![Derek App](https://alexellis.o6s.io/badge?owner=openfaas&repo=faas)](https://github.com/alexellis/derek/)