Update validation.php
Update validation.php

add "accepted_if"
see https://github.com/laravel/laravel/commit/e5962266d79ab4aa3b7e49d1d5cddb7f85c057e6#diff-9da20338be0e82c36209b49b11275ecb81652991cfe1fd252477d0dff42ddd0c
overtrue-forks/Laravel-lang,overtrue-forks/Laravel-lang