add minimum cost margin input box

backend/app/plugins/wiaas/includes/admin/pricing/views/html-package-pricing.php

@@ -144,6 +144,20 @@ if ( ! defined( 'ABSPATH' ) ) {
         });
 	</script>
 
+    <div class="options_group">
+        <?php
+        woocommerce_wp_text_input(
+	        array(
+		        'id'        => '_wiaas_minimum_cost_margin',
+		        'name'      => 'wiaas_minimum_cost_margin',
+		        'value'     => $minimum_cost_margin,
+		        'label'     => __( 'Minimum cost margin:', 'wiaas' ),
+		        'type'      => 'number',
+	        )
+        );
+        ?>
+    </div>
+
     <div class="options_group">
         <?php
         woocommerce_wp_text_input(