fix: Use Bootstrap 4 class names

payments/templates/pages/stripe_checkout.html

@@ -20,7 +20,7 @@
 		<h2 class="text-center">{{description}}</h2>
 		<form id="payment-form">
 			<div class="form-row row">
-				<div class="group col-xs-12">
+				<div class="group col-12">
 					<div>
 						<label>
 							<span>{{ _("Name") }}</span>
@@ -28,7 +28,7 @@
 					</label>
 					</div>
 				</div>
-				<div class="group col-xs-12">
+				<div class="group col-12">
 					<div>
 						<label>
 							<span>{{ _("Email") }}</span>
@@ -36,7 +36,7 @@
 					</label>
 					</div>
 				</div>
-				<div class="group col-xs-12">
+				<div class="group col-12">
 					<label>
 					<span>{{ _("Card Details") }}</span>
 				<div id="card-element" name="card-element" class="field"></div>