add language lines for before_or_equal and after_or_equal

resources/lang/en/validation.php

@@ -16,11 +16,13 @@ return [
     'accepted'             => 'The :attribute must be accepted.',
     'active_url'           => 'The :attribute is not a valid URL.',
     'after'                => 'The :attribute must be a date after :date.',
+    'after_or_equal'       => 'The :attribute must be a date after or equal to :date.',
     'alpha'                => 'The :attribute may only contain letters.',
     'alpha_dash'           => 'The :attribute may only contain letters, numbers, and dashes.',
     'alpha_num'            => 'The :attribute may only contain letters and numbers.',
     'array'                => 'The :attribute must be an array.',
     'before'               => 'The :attribute must be a date before :date.',
+    'before_or_equal'      => 'The :attribute must be a date before or equal to :date.',
     'between'              => [
         'numeric' => 'The :attribute must be between :min and :max.',
         'file'    => 'The :attribute must be between :min and :max kilobytes.',