title: Laravel at least one field is required
body: <p>I have two field <code>billable_option</code> and <code>billable_option_yes</code>. I want to validate at least one field is mandatory. I have tried:</p>
  
  <pre><code>$this-&gt;validate($request,[
      'billable_option'=&gt;'required'|'billable_option_yes'=&gt;'required',
  ]); 
  </code></pre>
  
  <p>I want to check at least one field is required in <code>Laravel-5.3</code>.</p>