Add back the device mac_address field
Add back the device mac_address field

Looks like this was accidentally removed during the
oclif refactor of `balena device`

Change-type: patch
See: https://github.com/balena-io/balena-cli/pull/1871
Signed-off-by: Thodoris Greasidis <5791bdc4541e79bd43d586e3c3eff1e39c16665f@balena.io>
resin-io/resin-cli,resin-io/resin-cli,resin-io/resin-cli,resin-io/resin-cli