Merge pull request #1 from zhaishuaigan/master

修复验证码不显示问题

src/CaptchaController.php

@@ -12,9 +12,8 @@
 namespace think\captcha;
 
 use think\Config;
-use think\Controller;
 
-class CaptchaController extends Controller
+class CaptchaController
 {
     public function index($id = "")
     {

src/helper.php

@@ -35,7 +35,7 @@ function captcha($id = "", $config = [])
  */
 function captcha_src($id = "")
 {
-    return \think\Url::build('/captcha' . $id ? "/{$id}" : '');
+    return \think\Url::build('/captcha' . ($id ? "/{$id}" : ''));
 }