Use v4 for Go Report Card

Author: dhui

README.md

@@ -5,7 +5,7 @@
 [![Docker Pulls](https://img.shields.io/docker/pulls/migrate/migrate.svg)](https://hub.docker.com/r/migrate/migrate/)
 ![Supported Go Versions](https://img.shields.io/badge/Go-1.18%2C%201.19-lightgrey.svg)
 [![GitHub Release](https://img.shields.io/github/release/golang-migrate/migrate.svg)](https://github.com/golang-migrate/migrate/releases)
-[![Go Report Card](https://goreportcard.com/badge/github.com/golang-migrate/migrate)](https://goreportcard.com/report/github.com/golang-migrate/migrate)
+[![Go Report Card](https://goreportcard.com/badge/github.com/golang-migrate/migrate/v4)](https://goreportcard.com/report/github.com/golang-migrate/migrate/v4)
 
 # migrate