[VOL-5296] document voltctl release

howto/release/voltctl/release.rst
  o Add more howto release notes for voltctl
    https://docs.voltha.org/master/howto/release/voltctl/release.html

Signed-off-by: Joey Armstrong <jarmstrong@linuxfoundation.org>
Change-Id: I1675d65ac57b6cd903626a1ab56b0d36ca058170
2 files changed