Mailinglist members pagination

[aisnoek]

The response for /lists/<address>/members/pages supports pagination, the class however did not.

By added the use of the Pagination trait it's now possible to use pagination.

Usage example:

$mailgun = Mailgun::create($apiKey, $endpoint);
$mailingListMembers = $mailgun->mailingList()->member();

$response = $mailingListMembers->index($address, 1000);

while ($response && count($response->getItems()) > 0) {
    $result = [...$result, ...$response->getItems()];

    $response = $mailingListMembers->nextPage($response);
}

Additionally the readme references composer test, composer.json however no longer contained that script. Restored it accordingly.

[mroeling]

@Nyholm @DavidGarciaCat Any e.t.a. of an updated version with this fix please?

[mroeling]

• bump @ZebulanStanphill Any e.t.a. of an updated version with this fix please?

[ZebulanStanphill]

@mroeling I'm not a maintainer of this project, so I have no clue, unfortunately.