List certificate requests made to CertCentral. You can filter by
    status: ``pending``, ``approved``, ``rejected``

    CLI Example:

    .. code-block:: bash

        salt-run digicert.list_requests pending

def list_requests(status=None):
    '''
    List certificate requests made to CertCentral. You can filter by
    status: ``pending``, ``approved``, ``rejected``

    CLI Example:

    .. code-block:: bash

        salt-run digicert.list_requests pending
    '''
    if status:
        url = '{0}/request?status={1}'.format(_base_url(), status)
    else:
        url = '{0}/request'.format(_base_url())

    reqs = _paginate(url,
                     "requests",
                     method='GET',
                     decode=True,
                     decode_type='json',
                     raise_error=False,
                     header_dict={
                         'X-DC-DEVKEY': _api_key(),
                         'Content-Type': 'application/json',
                     }
    )

    ret = {'requests': reqs}
    return ret