[RELEASE][VOTE] Release MXNet version 1.2.1.RC0

[Anirudh]

Hi all,

Apologies for replying instead of sending out a new email.

This vote has passed with 6 +1s:

Binding:
Sandeep
Haibin
Indhu

Non Binding:
Carin
Pedro
Lai

I will proceed with the vote on general@.

Thanks,
Anirudh