Update sakuracloud/resource_sakuracloud_disk.go
Update sakuracloud/resource_sakuracloud_disk.go

Co-Authored-By: yamamoto-febc <992e830136df35c0f18c07d2f1f456aac4dff67e@gmail.com>
sacloud/terraform-provider-sakuracloud,yamamoto-febc/terraform-provider-sakuracloud,sacloud/terraform-provider-sakuracloud,yamamoto-febc/terraform-provider-sakuracloud,yamamoto-febc/terraform-provider-sakuracloud,yamamoto-febc/terraform-provider-sakuracloud