How to setup php-watson-api-bridge to connect to Watson conversation API?

Using the php-watson-api-bridge, I am trying to connect with the Watson Conversation API to no avail (Getting 400 error).

I understand this question might be more useful directing it as issue to the repo as regard this so I did already.

Even though I managed to make a successful call to the API directly using Guzzle. I will appreciate if anyone has a (proven) way to use this bridge.

Here is what I have attempted so far:

$carpenter = app()->make(Carpenter::class);
$bridge = $carpenter->constructBridge('default', 'conversation');

$response = $bridge->get('https://gateway.watsonplatform.net/conversation/api/v1/workspaces', ['auth' => [
            env('WATSON_API_USERNAME'), env('WATSON_API_PASSWORD')
]]);

PS: If there is a need for more explanations, I am ready to provide.

Thanks in advance!