Added cache invalidation for products api

no refs

- adding/changing products needs cache invalidation header otherwise frontend endpoints like `/members/api/site` use cached product data
- adds cache invalidation for both add and edit endpoints for products

core/server/api/canary/products.js

@@ -66,6 +66,9 @@ module.exports = {
 
     add: {
         statusCode: 201,
+        headers: {
+            cacheInvalidate: true
+        },
         validation: {
             data: {
                 name: {required: true}
@@ -86,6 +89,7 @@ module.exports = {
         options: [
             'id'
         ],
+        headers: {},
         validation: {
             options: {
                 id: {
@@ -99,6 +103,12 @@ module.exports = {
                 frame.data,
                 frame.options
             );
+
+            if (model.wasChanged()) {
+                this.headers.cacheInvalidate = true;
+            } else {
+                this.headers.cacheInvalidate = false;
+            }
             return model;
         }
     }