Creates a signed upload URL. Signed upload URLs can be used to upload files to the bucket without further authentication. They are valid for 2 hours.
buckets table permissions: noneobjects table permissions: insertThe file path, including the current file name. For example `folder/image.png`.
const { data, error } = await supabase
  .storage
  .from('avatars')
  .createSignedUploadUrl('folder/cat.jpg')