force to int data_amount

force to int data_amount to use it in template with stripe checkout button:
    <script
        src="https://checkout.stripe.com/checkout.js" class="stripe-button"
        data-key="{{ form.stripeToken.field.widget.attrs.data_key }}"
        data-image="{{ STATIC_URL }}img/logo.png"
        data-name="Site Name"
        data-description="{{ form.stripeToken.field.widget.attrs.data_description }}"
        data-amount="{{ form.stripeToken.field.widget.attrs.data_amount }}"
        data-currency="{{ form.stripeToken.field.widget.attrs.data_currency }}">
    </script>