title: Check if a string is "0" with Laravel validation
body: <p>How can I check if a value of a string is "0" in Laravel 5.3?</p>
  
  <p>Here's my validation rules before processing the data:</p>
  
  <pre><code>// I want them to be anything but "0". So "01", "1" etc. are all okay
  $rules = [
      'state' =&gt; 'required',
      'city' =&gt; 'required',
  ];
  </code></pre>
  
  <p>As the data is passed as strings I cannot use min:1 for this.</p>
  
  <p>I'm sorry if this have already been asked, but I cannot find an answer. Many thanks!</p>