"Please provide a consent to track value." response when subscribing via XMLHttpRequest

[jpcarpenter]

While attempting to submit a subscribe form via XMLHttpRequest, the response returns a 404 with the following message:

reason: "Please provide a consent to track value."
statusCode: 400
success: false

I investigated within the CM API docs, and found that by adding a ConsentToTrack option to the subscriber list service, the response returns successfully. Below is where I added the option:

 $subscriber = array(
   'EmailAddress' => $email,
   'Name' => $fullName,
   'CustomFields' => $additionalFields,
   'Resubscribe' => true,
   "ConsentToTrack" => "Unchanged"
);

Once added, the subscribe functionality works as expected.

[heymarkreeves]

This has been addressed in #10, which updated the create-send library to resolve PHP's deprecated use of curly braces.