🤖 chore(package.json): Configure prettier.

These changes were automatically generated by a transform whose code can be found at:
  - https://github.com/aureooms/rejuvenate/blob/e086830dfe927964be93f46b8ecdacd2597eb487/src/transforms/prettier:config.js
Please contact the author of the transform if you believe there was an error.

Author: a-flying-potato

package.json

@@ -188,6 +188,9 @@
       }
     }
   },
+  "prettier": {
+    "trailingComma": "all"
+  },
   "xo": {
     "prettier": true,
     "plugins": [