Update main.go: fix token test

main.go

@@ -115,10 +115,10 @@ func main() {
 		data.Set("grant_type", grantType)
 		
 		client := &http.Client{}
-		r, _ := http.NewRequest("POST", tokenUrl, strings.NewReader(data.Encode())) // URL-encoded payload
-		r.Header.Add("Content-Type", "application/x-www-form-urlencoded")
+		req, _ := http.NewRequest("POST", tokenUrl, strings.NewReader(data.Encode()))
+		req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
 
-		response, err := client.Do(r)
+		response, err := client.Do(req)
 		fmt.Println(response.Status)
 		if err != nil {
 			fmt.Println(err)