title: mailjet API v3 reply-to not working
body: <p>I am using mailjet simple API v3 library to send emails. Here is the link:</p>
  
  <p><a href="https://github.com/mailjet/mailjet-apiv3-php-simple" rel="nofollow noreferrer">https://github.com/mailjet/mailjet-apiv3-php-simple</a></p>
  
  <p>Emails are sent successfully however reply to is not working.</p>
  
  <p>Below are the 2 attempts that I tried: </p>
  
  <pre><code>$params = array(
      "method" =&gt; "POST",
      "from" =&gt; $from_email,
      "to" =&gt; $to_email,
      "subject" =&gt; $subject,
      "html" =&gt; $message_body,
      "Headers" =&gt; [
                     "Reply-To" =&gt; $reply_to_email
                    ]
  );
  </code></pre>
  
  <p>And</p>
  
  <pre><code>$params = array(
      "method" =&gt; "POST",
      "from" =&gt; $from_email,
      "to" =&gt; $to_email,
      "subject" =&gt; $subject,
      "html" =&gt; $message_body,
      "Reply-To" =&gt; $reply_to_email
  );
  </code></pre>
  
  <p>I do not have option to install composer so I have to use this simple API.</p>