fix regex demo code

Author: mnphpexpert

README.md

@@ -549,13 +549,13 @@ User::where('name', 'regex', new \MongoDB\BSON\Regex("/.*doe/i"))->get();
 **NOTE:** you can also use the Laravel regexp operations. These are a bit more flexible and will automatically convert your regular expression string to a MongoDB\BSON\Regex object.
 
 ```php
-User::where('name', 'regexp', '/.*doe/i'))->get();
+User::where('name', 'regexp', '/.*doe/i')->get();
 ```
 
 And the inverse:
 
 ```php
-User::where('name', 'not regexp', '/.*doe/i'))->get();
+User::where('name', 'not regexp', '/.*doe/i')->get();
 ```
 
 **Type**