title: Php get dates inside a string
body: <p>I have a string like this:</p>
  
  <blockquote>
    <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean 2017-03-31 ligula eget dolor. Aenean massa. 2016-03-04 sociis natoque penatibus...</p>
  </blockquote>
  
  <p>I would like to get all the dates inside the text... the format dates are always <code>yyyy-mm-dd</code>.</p>
  
  <p>Any suggestions?</p>