function _headersMatchRule(headers, allowedHeaders) {
    if (!allowedHeaders) {
        return false;
    }
    if (!headers.every(header => _matchesOneOf(allowedHeaders, header))) {
        return false;
    }
    return true;
}
_headersMatchRule - check if headers match AllowedHeaders of rule
@param {string[]} headers - the value of the 'Access-Control-Request-Headers'
  in an OPTIONS request
@param {string[]} allowedHeaders - AllowedHeaders of a CORS rule
@return {boolean} - true/false