hotfix: Add thumbnail to product seed data

data/seed.json

@@ -39,7 +39,7 @@
         "handle": "basic-shirt",
         "is_giftcard": false,
         "images": [],
-        "thumbnail": "",
+        "thumbnail": "https://medusa-public-images.s3.eu-west-1.amazonaws.com/tote-bag-2+1.svg",
         "options": [
           {
             "title": "Size"