Make PendingRequest Conditionable

[phillipfickl]

This pull request makes PendingRequest Conditionable.

It will let you use when() and unless() to make the code a bit more readable.
Example where I would have used it:

$this->http = Http::withBasicAuth(
            $username,
            $password
        );

        if (app()->environment('local')) {
            $this->http->withoutVerifying();
        }
        
        if ($baseUrl !== null) {
            $this->http->baseUrl($baseUrl);
        }

becomes

$this->http = Http::withBasicAuth(
            $username,
            $password
        )->when(app()->environment('local'), function (PendingRequest $request) {
            $request->withoutVerifying();
        })->when($baseUrl !== null, function (PendingRequest $request) {
            $request->baseUrl($baseUrl);
        });