Correct PromotionalOfferSignatureCreator example

Author: alexanderjordanbaker

README.md

@@ -117,9 +117,11 @@ const encodedKey = readFile(filePath) // Specific implementation may vary
 const productId = "<product_id>"
 const subscriptionOfferId = "<subscription_offer_id>"
 const applicationUsername = "<application_username>"
+const nonce = "<nonce>"
+const timestamp = Date.now()
 const signatureCreator = new PromotionalOfferSignatureCreator(encodedKey, keyId, bundleId)
 
-const signature = signatureCreator.createSignature(productId, subscriptionOfferId, signatureCreator)
+const signature = signatureCreator.createSignature(productId, subscriptionOfferId, applicationUsername, nonce, timestamp)
 console.log(signature)
 ```