Dockerfile: MAINTAINER is deprecated
Dockerfile: MAINTAINER is deprecated

The MAINTAINER command is deprecated. MAINTAINER is deprecated in
favor of using LABEL since Docker v1.13.0.

https://github.com/docker/cli/blob/master/docs/deprecated.md#maintainer-in-dockerfile

Change-Id: I21940dba5179eb8ce40c6d73d1a13e379493d68e

redhat-cip/python-dciclient,redhat-cip/python-dciclient