Please support param bill_immediately

[longseespace]

paddle-sdk/sdk.js

Line 410 in 55112c7

updateSubscriptionPlan(subscriptionID, planID, prorate = false) {

[longseespace]

Looks like the PR is in review #35

[longseespace]

This is more of a question than a request.

Hey @avaly, while I'm still waiting for the PR to be merged, is it correct that I could use this API to achieve the same:

paddle-sdk/sdk.js

Line 432 in 55112c7

updateSubscription(subscriptionID, postData) {

client.updateSubscription(<subscription_id>, {
  planID: <plan_id>,
  billImmediately: true,
});

Thanks.