fixed heroku deploy error

pages/index.vue

@@ -75,7 +75,7 @@ export default {
       // }
       courses : state => state.course.items,
       featuredBlogs: state => state.blog.items.featured,
-      courseHero: state => state.hero.item
+      courseHero: state => state.hero.item || {}
     })
   },
   async fetch({store}) {

store/hero.js

@@ -1,5 +1,5 @@
 export const state = () => ({
-  item: null
+  item: {}
 })