🤖 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/67ba7d5e9b38c8944d42909a3a30b0710559b446/src/transforms/prettier:config.js
Please contact the author of the transform if you believe there was an error.

Author: a-flying-potato

Diff for: package.json

@@ -215,5 +215,8 @@
         ]
       }
     }
+  },
+  "prettier": {
+    "trailingComma": "all"
   }
 }