Update README.md

[nurbxfit]

Update the example code
from:

 if (ticket.id) {
    receiptIds.push(ticket.id);
  }

to

 if (ticket.status == "ok") { // doing this help with typescript error
  receiptIds.push(ticket.id)
}

The typescript Error:

Property 'id' does not exist on type 'ExpoPushTicket'.
Property 'id' does not exist on type 'ExpoPushErrorReceipt'.

this is due to the type being declare like this

export type ExpoPushReceiptId = string;

export type ExpoPushSuccessTicket = {
  status: 'ok';
  id: ExpoPushReceiptId;
};

export type ExpoPushErrorTicket = ExpoPushErrorReceipt;

export type ExpoPushTicket = ExpoPushSuccessTicket | ExpoPushErrorTicket;

in src/ExpoClient.ts

the id surely exist if the status == 'ok'