title: Symfony : Validate email parameter with ParamFetcher
body: <p>Dears,</p>
  
  <p>I want to validate email directly in the RequestParam.
  I'm using this kind of REGEX: </p>
  
  <pre><code>[a-z0-9!#$%&amp;'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&amp;'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?
  </code></pre>
  
  <p>But the parser failed to load the regex in requirements option</p>
  
  <pre><code>The parameter \"&amp;'*+/=?^_`{|}~-]+(?:\\.[a-z0-9!#$\" must be defined.
  </code></pre>
  
  <p>How could I validate email something like that:</p>
  
  <pre><code>/**
   * @Rest\Patch(
   *     "v1/customer/update",
   *     name="Update a customer"
   * )
   * @RequestParam(
   *     name="email",
   *     requirements="email",
   *     description="The email of the user",
   *     strict=true
   *     )
   */
  </code></pre>
  
  <p>Thanks in advance</p>