[1.7.x] Fix serialize

[lukecurtis93]

Hi there 👋

Thanks for a great package!

When using the default serialize class in the changed file on the PR it actually edits the original variable therefore if you were to send the message twice (for whatever reason) it would serialize twice.. I've attached a screen grab of this happening in the kafka cluster.

You can replicate with the below

use Junges\Kafka\Facades\Kafka;
use Junges\Kafka\Message\Message;

$message = new Message(
    body: ['key' => 'value'],
);

Kafka::publishOn('test-topic')->withMessage($message)->send();
Kafka::publishOn('test-topic')->withMessage($message)->send();

This PR simply clones the message - please let me know if you'd prefer a different approach

[mateusjunges]

Hi @lukecurtis93 can you please add a test for this case?

[mateusjunges]

Also, i think we should target v1.6.x for this fix

[lukecurtis93]

for sure mate no worries 😊 will update asap

[mateusjunges]

Thank you. I'll close this and merge #92