Change deprecated pushHandler to prependHandler
Change deprecated pushHandler to prependHandler

On https://github.com/filp/whoops/blob/master/src/Whoops/Run.php on lines 43-54, it states that pushHandler is being replaced with prependHandler.

Specifically:
* @deprecated use appendHandler and prependHandler instead
     */
    public function pushHandler($handler)
    {
        return $this->prependHandler($handler);
    }
filp/whoops,filp/whoops,michabbb-backup/whoops,michabbb-backup/whoops