close #2941 Fixed: If you enter string invoice next_number, duplicate and auto upper broken ( #8669n1g9v )

app/Http/Requests/Setting/Setting.php

@@ -45,6 +45,10 @@ class Setting extends FormRequest
             $rules['number_digit'] = 'required|integer|min:1|max:20';
         }
 
+        if ($this->request->has('number_next')) {
+            $rules['number_next'] = 'required|integer';
+        }
+
         return $rules;
     }