Fixed pay invoice method and updated testcase

Author: ppatidar2021

src/main/java/com/bitpay/sdk/Client.java

@@ -468,9 +468,10 @@ public Invoice updateInvoice(String invoiceId, String buyerSms, String smsCode,
      * @throws BitPayException        BitPayException class
      * @throws InvoiceUpdateException InvoiceUpdateException class
      */
-    public Invoice payInvoice(String invoiceId, Boolean complete) throws BitPayException, InvoiceUpdateException {
+    public Invoice payInvoice(String invoiceId, String status, Boolean complete) throws BitPayException, InvoiceUpdateException {
         final Map<String, Object> params = new HashMap<>();
         params.put("token", this.getAccessToken(Facade.Merchant));
+        params.put("status", status);
         if (complete == null) {
             throw new InvoiceUpdateException(null, "It is required to define the whether the invoice will be set to \"complete\" or \"confirmed\".");
         }

src/test/java/test/BitPayTestMerchant.java

@@ -311,7 +311,7 @@ public void testShouldCreateAndPayInvoice() {
         Invoice invoice = new Invoice(1.0, "USD");
         try {
             basicInvoice = bitpay.createInvoice(invoice);
-            paidInvoice = bitpay.payInvoice(basicInvoice.getId(), true);
+            paidInvoice = bitpay.payInvoice(basicInvoice.getId(), "confirmed", true);
         } catch (Exception e) {
             e.printStackTrace();
             fail(e.getMessage());