title: Google Pay button not showing on Real Device using the pay Plugin Flutter
body: <p>I was trying to implement the <em>pay</em> plugin of Flutter. But the Google Pay button is not showing on a real device. It shows up in the Emulator.</p>
  <p>This is the plugin I am using</p>
  <pre><code>pay: ^1.0.6
  </code></pre>
  <p>And this is my code for showing the payment buttons:</p>
  <pre><code>var _paymentItems = [
      PaymentItem(
        label: 'Total',
        amount: '99.99',
        status: PaymentItemStatus.final_price,
      )
    ];
  
  
  GooglePayButton(
                      paymentConfigurationAsset: 'gpay.json',
                      paymentItems: _paymentItems,
                      width: 200,
                      height: 50,
                      style: GooglePayButtonStyle.white,
                      type: GooglePayButtonType.pay,
                      margin: const EdgeInsets.only(top: 15.0),
                      onPaymentResult: onGooglePayResult,
                      loadingIndicator: const Center(
                        child: CircularProgressIndicator(),
                      ),
                    )
  </code></pre>
  <p>Is there any restriction for using <strong>Google pay</strong>?</p>
  <p>I am from Bangladesh and I tried running on different devices, it's showing on none.</p>
  <p>I will highly appreciate any kind of help. Thanks in advance.</p>