Require Postcode, Country ID, City to get Rates.

uafrica/Customshipping/view/frontend/web/js/model/shipping-rates-validation-rules.js

@@ -10,7 +10,15 @@ define(
         return {
             getRules: function() {
                 return {
-
+                    'postcode': {
+                        'required': true
+                    },
+                    'country_id': {
+                        'required': true
+                    },
+                    'city': {
+                        'required': true
+                    }
                 };
             }
         };