chore: update usage of minio admin library (#28)

* chore: update usage of minio admin library

madmin/NOTICE

@@ -0,0 +1,9 @@
+MinIO Cloud Storage, (C) 2014-2020 MinIO, Inc.
+
+This product includes software developed at MinIO, Inc.
+(https://min.io/).
+
+The MinIO project contains unmodified/modified subcomponents too with
+separate copyright notices and license terms. Your use of the source
+code for these subcomponents is subject to the terms and conditions
+of Apache License Version 2.0