docs(readme): fix code link (#989)

README.md

@@ -471,7 +471,7 @@ func startPage(c *gin.Context) {
 	var person Person
 	// If `GET`, only `Form` binding engine (`query`) used.
 	// If `POST`, first checks the `content-type` for `JSON` or `XML`, then uses `Form` (`form-data`).
-	// See more at https://github.com/gin-gonic/gin/blob/develop/binding/binding.go#L45
+	// See more at https://github.com/gin-gonic/gin/blob/master/binding/binding.go#L48
 	if c.Bind(&person) == nil {
 		log.Println(person.Name)
 		log.Println(person.Address)